//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
#include <algorithm>
using namespace std;
typedef long long ll;
typedef __int128 lll;
//typedef __float128 fl;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<ull> vull;
typedef vector<lll> vlll;
typedef pair<int, int> pi;
typedef pair<ll, ll> pll;
const ll INF = LONG_LONG_MAX - 1;
const int MOD = 1e9 + 7;
const int MOD2 = 998244353;
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};
const double PI = 3.14159265358979323846;
#define fast_io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define print(a) cout << (a) << "\n";
#define printPair(a) cout << (a).first << " " << (a).second << "\n";
#define debug(...) fprintf(stderr, __VA_ARGS__), fflush(stderr)
#define time__(d) \
for ( \
auto blockTime = make_pair(chrono::high_resolution_clock::now(), true); \
blockTime.second; \
debug("%s: %lld ms\n", d, chrono::duration_cast<chrono::milliseconds>(chrono::high_resolution_clock::now() - blockTime.first).count()), blockTime.second = false \
)
//Mint fact[MAXN + 3];
//Mint inv[MAXN + 3];
double TOL = 1e-7;
void preload(){
// sieve(MAXN);
}
ll bS(const vector<ll>& b, const vector<ll>& psumEnd, ll x) {
// Find the first index where b[i] >= x.
int idx = lower_bound(b.begin(), b.end(), x) - b.begin();
// For indices i < idx, we add (x - b[i]). The sum is then:
// idx * x - (b[0] + b[1] + ... + b[idx-1])
return idx * x - psumEnd[idx];
}
ll cS(const vector<ll>& c, const vector<ll>& psumStart, ll x) {
// Find the first index where c[i] > x.
int idx = upper_bound(c.begin(), c.end(), x) - c.begin();
int n = c.size();
// Sum of elements from idx to n-1 is psumStart[n] - psumStart[idx]
ll sumOverElements = psumStart[n] - psumStart[idx];
// Each of these (n-idx) elements contributes a subtraction of x.
return sumOverElements - (n - idx) * x;
}
void solve(int& tc) {
int k,n;
cin >> k >> n;
vector<pi> a;
ll ans = 0;
vll b;
vll c;
for (int i = 0; i < n; ++i){
char z1,z2;
int p1,p2;
cin >> z1 >> p1 >> z2 >> p2;
if (z1 == z2){
ans += abs(p2-p1);
} else {
a.emplace_back(min(p1,p2),max(p1,p2));
b.emplace_back(min(p1,p2));
c.emplace_back(max(p1,p2));
}
}
n = a.size();
ans += n;
sort(b.begin(),b.end());
sort(c.begin(),c.end());
ll s = 0;
for (int i = 0; i < n; ++i)
s += a[i].second-a[i].first;
vll psumStart;
psumStart.emplace_back(0);
vll psumEnd;
psumEnd.emplace_back(0);
for (int i = 0; i < n; ++i){
psumStart.emplace_back(psumStart.back() + b[i]);
psumEnd.emplace_back(psumEnd.back() + c[i]);
}
ll gans = INF/3;
for (int i = 0; i < n; ++i){
ll x = a[i].first;
ll temp = 2ll*(bS(c,psumEnd,x) + cS(b,psumStart,x));
gans = min(gans,temp);
x = a[i].second;
temp = 2ll*(bS(c,psumEnd,x) + cS(b,psumStart,x));
gans = min(gans,temp);
}
print(ans + s + gans);
}
int main() {
fast_io;
int t;
t = 1;
// cin >> t;
time__("solve") {
preload();
int x = 0;
while (t-- > 0) {
x++;
solve(x);
}
}
return 0;
}
