#include <bits/stdc++.h>
using namespace std;
#define int long long
int K, N, ext, ans, c, suf[1<<17];
vector<array<int, 2>> a;
priority_queue<int> L, R;
void put(int v) {
if(empty(L) || v <= L.top())
L.push(+v), c -= v;
else
R.push(-v), c += v;
if(size(L) < size(R))
L.push(v = -R.top()), R.pop(), c -= v*2;
if(size(L) > size(R) + 1)
R.push(v = -L.top()), L.pop(), c -= v*2;
}
int32_t main() {
ios::sync_with_stdio(0), cin.tie(0);
cin >> K >> N;
for(int i = 0, s, t; i < N; ++i) {
char p, q;
cin >> p >> s >> q >> t;
if(p == q) ext += abs(t - s);
else
++ext, a.push_back({s, t});
}
N = size(a);
sort(begin(a), end(a) , [&](const auto &i, const auto &j) {
return i[0] + i[1] < j[0] + j[1];
});
for(int i = N; i--; ) {
put(a[i][0]), put(a[i][1]);
ans = suf[i] = c;
}
if(K > 1) {
L = R = priority_queue<int> (), c = 0;
for(int i = 0; i < N; ++i) {
put(a[i][0]), put(a[i][1]);
ans = min(ans, c + suf[i+1]);
}
}
cout << ans + ext;
}
