#include <bits/stdc++.h>
using namespace std;
using ll = long long;
ll f(vector<int> &v) {
ll res = 0;
sort(v.begin(), v.end());
for (int j = 0; j < (int)v.size(); j++) res += (j < (int)v.size() >> 1 ? -1 : 1) * v[j];
return res;
}
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});
}
if (v.empty()) return cout << sm, 0;
sm += (int)v.size();
vector<int> u;
for (auto i : v) u.insert(u.end(), {i[1], i[2]});
if (K == 1) return cout << sm + f(u), 0;
ll mn = LLONG_MAX;
sort(v.begin(), v.end());
for (int i = 1; i < (int)v.size() - 1; i++) {
vector<int> u1, u2;
for (int j = 0; j < (int)v.size(); j++) {
for (auto k : {v[j][1], v[j][2]}) {
(j <= i ? u1 : u2).push_back(k);
}
}
mn = min(mn, f(u1) + f(u2));
}
cout << sm + mn;
}
