// Cao Quang Hung
#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
using namespace std;
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define pii pair<int,int>
#define pll pair<long long , long long>
#define vi vector<int>
#define vpii vector<pii>
#define SZ(x) ((int)(x.size()))
#define fi first
#define se second
#define IN(x,y) ((y).find((x))!=(y).end())
#define ALL(t) t.begin(),t.end()
#define FOREACH(i,t) for (typeof(t.begin()) i=t.begin(); i!=t.end(); i++)
#define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
#define REPD(i,a,b) for(int (i)=(a); (i)>=(b);--i)
#define FOR(i, n) for (int (i) = 0; (i) < (n); ++(i))
#define dem(x) __builtin_popcount(x)
#define Mask(x) (1LL << (x))
#define BIT(x, i) ((x) >> (i) & 1)
#define ln '\n'
#define io_faster ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
///mt19937 rnd(time(0));
const int INF = 1e9 , mod = 1e9 + 7;
template <class T1, class T2>
inline T1 mul(T1& x, const T2 &k){ return x = (1LL * x * k) % mod; }
template <class T1 , class T2>
inline T1 pw(T1 x, T2 k){T1 res = 1; for (; k ; k >>= 1){ if (k & 1) mul(res, x); mul(x, x); } return res;}
template <class T>
inline bool minimize(T &x, const T &y){ if (x > y){x = y; return 1;} return 0; }
template <class T>
inline bool maximize(T &x, const T &y){ if (x < y){x = y; return 1;} return 0; }
template <class T>
inline void add(T &x , const T &y){ if ((x += y) >= mod) x -= mod; }
template <class T>
inline T product (const T &x , const T &y) { return 1LL * x * y % mod; }
#define PROB "a"
void file(){
if(fopen(PROB".inp", "r")){
freopen(PROB".inp","r",stdin);
freopen(PROB".out","w",stdout);
}
}
void sinh_(){
// srand(time(0));
// freopen(PROB".inp" , "w" , stdout);
// int n;
}
typedef long long ll;
typedef double db;
const int N = 2e5 + 5;
int k, n;
ll Ans = 0;
pii segment[N];
int numseg = 0, numpoint;
vector<int> compress;
void readip(){
cin >> k >> n;
REP(i, 1, n) {
char a, b; int l, r;
cin >> a >> l >> b >> r;
Ans += abs(r - l);
if (a == b) continue;
++Ans;
if (l > r) swap(l, r);
segment[++numseg] = {l, r};
compress.eb(l);
compress.eb(r);
}
sort(ALL(compress));
compress.erase(unique(ALL(compress)), compress.end());
numpoint = compress.size();
if (numpoint == 0) {
cout << Ans << ln;
exit(false);
}
sort(segment + 1, segment + numseg + 1);
REP(i, 1, numseg) {
segment[i].first = lower_bound(ALL(compress), segment[i].first) - compress.begin() + 1;
segment[i].second = lower_bound(ALL(compress), segment[i].second) - compress.begin() + 1;
}
}
namespace sub1 {
bool check() {
return k == 1;
}
vector<pair<ll, int>> pref, suf;
void solve() {
pref.assign(numpoint + 2, {0, 0});
suf.assign(numpoint + 2, {0, 0});
REP(i, 1, numseg) {
pref[segment[i].second].first += compress[segment[i].second - 1];
pref[segment[i].second].second++;
suf[segment[i].first].first += compress[segment[i].first - 1];
suf[segment[i].first].second++;
}
REP(i, 1, numpoint) {
pref[i].first += pref[i - 1].first;
pref[i].second += pref[i - 1].second;
}
REPD(i, numpoint - 1, 1) {
suf[i].first += suf[i + 1].first;
suf[i].second += suf[i + 1].second;
}
ll res = 1e18;
REP(i, 1, numpoint) {
int x = compress[i - 1];
ll tmp = 1LL * x * pref[i].second - pref[i].first
+ suf[i].first - 1LL * x * suf[i].second;
tmp *= 2;
minimize(res, tmp);
}
cout << Ans + res << ln;
}
};
namespace subfull {
vector<int> lef_median, rig_median;
vector<ll> totLef, totRig;
struct segtree {
vector<int> it;
segtree(int sz = 0) {
if (sz > 0)
it.assign(4 * sz + 7, 0);
}
void upd(int i, int inc, int id = 1, int l = 1, int r= numpoint) {
while(1) {
it[id] += inc;
if (l == r) return;
int mid = (l + r) >> 1;
if (i <= mid) id = id << 1, r = mid;
else id = id << 1 | 1, l = mid + 1;
}
}
int walk(int val, int id = 1, int l = 1, int r = numpoint) {
while(1) {
if (l == r) return l;
int mid = (l + r) >> 1;
if (val > it[id << 1]) {
val -= it[id << 1];
id = id << 1 | 1;
l = mid + 1;
}
else {
id = id << 1;
r = mid;
}
}
}
} ST;
struct fenwick{
vector<pair<ll, int>> fen;
fenwick(int sz = 0) {
if (sz > 0)
fen.assign(sz + 7, {0LL, 0});
}
void upd(int i, pair<int, int> val) {
for (; i <= numpoint; i += i & -i)
fen[i].fi += val.fi , fen[i].se += val.se;
}
pair<ll, int> get(int i) {
pair<ll, int> res(0LL, 0);
for (; i > 0; i -= i & -i) {
res.fi += fen[i].fi;
res.se += fen[i].se;
}
return res;
}
} Fen;
void solve() {
lef_median.assign(numseg + 2, 0);
rig_median.assign(numseg + 2, 0);
totLef.assign(numseg + 2, 0LL);
totRig.assign(numseg + 2, 0LL);
ST = segtree(numpoint);
Fen = fenwick(numpoint);
REP(i, 1, numseg) {
Fen.upd(segment[i].fi, {compress[segment[i].fi - 1], +1});
Fen.upd(segment[i].se, {compress[segment[i].se - 1], +1});
ST.upd(segment[i].fi, +1);
ST.upd(segment[i].se, +1);
lef_median[i] = ST.walk(i);
pair<ll, int> tmp = Fen.get(lef_median[i]);
totLef[i] += 1LL * (compress[lef_median[i] - 1]) * tmp.se - tmp.fi;
pair<ll, int> temp = Fen.get(numpoint);
temp.fi -= tmp.fi;
temp.se -= tmp.se;
totLef[i] += temp.fi - 1LL * (compress[lef_median[i] - 1]) * temp.se;
}
REP(i, 1, numseg) {
ST.upd(segment[i].fi, -1);
ST.upd(segment[i].se, -1);
Fen.upd(segment[i].fi, {-compress[segment[i].fi - 1], -1});
Fen.upd(segment[i].se, {-compress[segment[i].se - 1], -1});
}
REPD(i, numseg, 1) {
Fen.upd(segment[i].fi, {compress[segment[i].fi - 1], +1});
Fen.upd(segment[i].se, {compress[segment[i].se - 1], +1});
ST.upd(segment[i].fi, +1);
ST.upd(segment[i].se, +1);
rig_median[i] = ST.walk(numseg - i + 1);
pair<ll, int> tmp = Fen.get(rig_median[i] - 1);
totRig[i] += 1LL * compress[rig_median[i] - 1] * tmp.se - tmp.fi;
pair<ll, int> temp = Fen.get(numpoint);
temp.fi -= tmp.fi;
temp.se -= tmp.se;
totRig[i] += temp.fi - 1LL * (compress[rig_median[i] - 1]) * temp.se;
}
ll res = 1e18;
REP(i, 1, numseg - 1)
minimize(res, totLef[i] + totRig[i + 1]);
cout << Ans + res << ln;
}
};
void solve(){
if (sub1::check()) {
sub1::solve();
return;
}
if (numpoint <= 2) {
cout << Ans << ln;
return;
}
REP(i, 1, numseg) Ans -= compress[segment[i].se - 1] - compress[segment[i].fi - 1];
sort(segment + 1, segment + numseg + 1, [&] (const pii &x, const pii &y) {
return compress[x.fi - 1] + compress[x.se - 1] < compress[y.fi - 1] + compress[y.se - 1];
});
subfull::solve();
}
int main(){
sinh_();
io_faster
file();
int t = 1;
// cin >> t;
while (t--){
readip();
solve();
}
}
