#include <bits/stdc++.h>
#define bit(i, x) (x >> i & 1)
#define ll long long
const int N = 2e5 + 5;
const int mod = 998244353;
using namespace std;
int k, n;
vector<pair<int, int>> a;
ll bonus;
signed main(int argc, char* argv[]) {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> k >> n;
for(int i = 1; i <= n; i++) {
char p, q; int s, t;
cin >> p >> s >> q >> t;
if(p == q) {
bonus += abs(t - s);
continue;
}
bonus++;
a.push_back({min(s, t), max(s, t)});
// auto [x, y] = a.back();
// cout << x << " " << y << "\n";
}
ll res = 2e18;
for(auto i : a) {
int t = i.first;
ll val = 0;
for(auto j : a) {
val += abs(j.first - t) + abs(j.second - t);
}
res = min(res, val);
t = i.second;
val = 0;
for(auto j : a) {
val += abs(j.first - t) + abs(j.second - t);
}
res = min(res, val);
}
cout << res + bonus;
return 0 ^ 0;
}
