#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
int K, n;
cin >> K >> n;
ll sm = 0;
vector<vector<int>> v;
for (int i = 0; i < n; i++) {
char p, q;
int s, t;
cin >> p >> s >> q >> t;
if (p == q) sm += abs(t - s);
else v.push_back({s + t, s, t});
}
sm += (int)v.size();
sort(v.begin(), v.end());
vector<int> u;
for (auto i : v) u.insert(u.end(), {i[1], i[2]});
if (K == 1) {
sort(u.begin(), u.end());
for (int j = 0; j < (int)u.size(); j++) sm += (j < (int)u.size() >> 1 ? -1 : 1) * u[j];
return cout << sm, 0;
}
ll mn = LLONG_MAX;
for (int i = 0; i < (int)u.size(); i++) {
for (int j = i; j < (int)u.size(); j++) {
ll sm = 0;
for (auto k : v) sm += min(abs(k[1] - u[i]) + abs(k[2] - u[i]), abs(k[1] - u[j]) + abs(k[2] - u[j]));
mn = min(mn, sm);
}
}
cout << sm + mn;
}
