#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int N = 1e5 + 5;
ll jogap, a[N], b[N];
int n, k;
char oy[N], of[N];
ll hasapla (ll x) {
ll ret = 0;
for (int i = 1; i <= n; ++i) {
if (oy[i] == of[i]) {
ret += abs (a[i] - b[i]);
}
else {
ret += abs (a[i] - x) + abs (x - b[i]) + 1;
}
}
return ret;
}
int main () {
// freopen ("input.txt", "r", stdin);
cin >> k >> n;
for (int i = 1; i <= n; ++i) {
cin >> oy[i] >> a[i] >> of[i] >> b[i];
}
// return cout << n << " " << k, 0;
// for (int i = 1; i <= n; ++i) {
// cout << i << " --> " << oy[i] << " " << a[i] << " " << of[i] << " " << b[i] << "\n";
// }
// return 0;
jogap = 2e18;
for (int i = 1; i <= n; ++i) {
jogap = min ({jogap, hasapla(a[i]), hasapla (b[i])});
}
cout << jogap;
}
