#include <bits/stdc++.h>
using namespace std;
#define FAST_IO ios_base::sync_with_stdio(0); cin.tie(nullptr)
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define REP(n) FOR(O, 1, (n))
#define pb push_back
#define f first
#define s second
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vii;
const int MAXN = 500100;
const ll INF = (ll)1e17;
int k, nn, n;
ll s[MAXN], t[MAXN];
vl pts;
set<ll> tmp;
map<ll, int> toId;
ll ans;
vector<pair<ll, int>> sortedS, sortedT, sortedST;
ll closed[MAXN], notOpened[MAXN];
void preCalc () {
/// compression of points
FOR(i, 1, n) {
tmp.insert(s[i]);
tmp.insert(t[i]);
}
ll id = 0;
for (ll x : tmp) {
pts.pb(x);
toId[x] = id;
id++;
}
/// sortedS and sortedT
FOR(i, 1, n) {
sortedS.pb({s[i], i});
sortedT.pb({t[i], i});
sortedST.pb({s[i] + t[i], i});
}
sort(sortedS.begin(), sortedS.end());
sort(sortedT.begin(), sortedT.end());
sort(sortedST.begin(), sortedST.end());
/// closed and notOpen calc
notOpened[0] = n;
FOR(i, 1, n) {
notOpened[toId[s[i]]]--;
closed[toId[t[i]]]++;
}
FOR(i, 1, (int)pts.size()-1) {
notOpened[i] += notOpened[i-1];
closed[i] += closed[i-1];
}
}
void solve1 () {
//ll curMin = INF;
ll cur = 0;
int ch = 0;
FOR(i, 0, (int)pts.size()-1) {
if (closed[i] >= notOpened[i]) {
ch = pts[i];
break;
}
}
FOR(i, 1, n) {
cur += abs(s[i] - ch) + abs(t[i] - ch);
}
ans += cur;
cout << ans << "\n";
}
void solve2 () {
ll cur = 0;
ll minCur = INF;
FOR(aa, 0, (int)pts.size()-2) {
ll b1 = pts[aa];
ll b2 = pts[aa+1];
cur = 0;
FOR(i, 1, n) {
ll cr1 = abs(s[i] - b1) + abs(t[i] - b1);
ll cr2 = abs(s[i] - b2) + abs(t[i] - b2);
cur += min(cr1, cr2);
}
minCur = min(minCur, cur);
//cout << " b1 = " << b1 << " b2 = " << b2 << " cur = " << cur << endl;
int idS = 0, idT = 0, idST = 0;
int cl = 0, notOp = n;
while (idS < n && sortedS[idS].f <= b2) {
idS++;
notOp--;
}
while (idT < n && sortedT[idT].f <= b2) {
int id = sortedT[idT].s;
if (s[id] > b1)
cl++;
idT++;
//cl++;
}
while (idST < n && sortedST[idST].f <= b1+b2) {
int id = sortedST[idST].s;
if (s[id] > b1)
cl--;
idST++;
//cl--;
}
FOR(bb, aa+2, (int)pts.size()-1) {
b2 = pts[bb];
ll d = b2 - pts[bb-1];
//cout << " d = " <<d << " cl = " << cl << " notOp = " << notOp << endl;
cur += d * 2 * (cl - notOp);
while (idS < n && sortedS[idS].f <= b2) {
idS++;
notOp--;
}
while (idT < n && sortedT[idT].f <= b2) {
int id = sortedT[idT].s;
if (s[id] > b1)
cl++;
idT++;
//cl++;
}
while (idST < n && sortedST[idST].f <= b1+b2) {
int id = sortedST[idST].s;
if (s[id] > b1) {
cur -= abs(b2 - s[id]) + abs(b2 - t[id]);
cur += abs(s[id] - b1) + abs(t[id] - b1);
cl--;
}
idST++;
//cl--;
}
//cout << " b1 = " << b1 << " b2 = " << b2 << " cur = " << cur << endl;
minCur = min(minCur, cur);
}
}
ans += minCur;
//cout << " minCur = " << minCur << endl;
cout << ans << "\n";
}
int main()
{
FAST_IO;
cin >> k >> nn;
FOR(i, 1, nn) {
char pp, qq;
ll ss, tt;
cin >> pp >> ss >> qq >> tt;
if (pp == qq) {
ans += abs(ss-tt);
} else {
n++;
ans++;
//ans += abs(ss-tt);
s[n] = min(ss,tt);
t[n] = max(ss,tt);
}
}
//cout << " ans = " << ans << endl;
preCalc();
if (k == 1) {
solve1();
return 0;
} else {
solve2();
return 0;
}
return 0;
}
/*
in:
1 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
ans: 24
in:
2 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
ans: 22
*/
