#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
int k, n;
cin >> k >> n;
ll ans = 0;
vector<ll> vi;
vector<pair<int, int>> vpii;
for (int i = 0; i < n; i++) {
char a, b;
int x, y;
cin >> a >> x >> b >> y;
if (a == b) {
ans += abs(y - x);
} else {
vpii.push_back(minmax(x, y));
ans++;
}
}
sort(vpii.begin(), vpii.end(), [&](pair<int, int> a, pair<int, int> b) {
return (a.first + a.second) < (b.first + b.second);
});
vector<ll> pref(vpii.size() + 1), suf(vpii.size() + 1);
pref[0] = 0;
priority_queue<int> pqi;
ll sm = 0, sm2 = 0;
ll ct2 = 0;
auto ins = [&](int x) {
pqi.push(x);
sm += x;
if (pqi.size() > ct2 + 1) {
ct2++;
sm2 += pqi.top();
sm -= pqi.top();
pqi.pop();
}
};
for (int i = 1; i <= vpii.size(); i++) {
ins(vpii[i - 1].first), ins(vpii[i - 1].second);
ll x = pqi.top();
pref[i] = (x * pqi.size() - sm) + (sm2 - x * ct2);
}
pqi = priority_queue<int>();
suf[vpii.size()] = 0;
sm = sm2 = ct2 = 0;
for (int i = ((int)(vpii.size())) - 1; i >= 0; i--) {
ins(vpii[i].first), ins(vpii[i].second);
ll x = pqi.top();
suf[i] = (x * pqi.size() - sm) + (sm2 - x * ct2);
}
// cout << "VPII:\n";
// for (auto a : vpii)
// cout << a.first << " " << a.second << "\n";
// cout << "\n";
//
// for (auto a : pref)
// cout << a << " ";
// cout << "\n";
// for (auto a : suf)
// cout << a << " ";
// cout << "\n";
ll minans = LLONG_MAX;
for (int i = 0; i <= vpii.size(); i++) {
minans = min(minans, ans + suf[i] + pref[i]);
}
cout << minans << "\n";
}
