#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
struct med {
ll as, bs;
priority_queue<int> a;
priority_queue<int, vector<int>, greater<int>> b;
med() : as(0), bs(0) {}
void resz() {
while (a.size() >= b.size() + 2) {
int e = a.top();
as -= e;
a.pop();
b.push(e);
bs += e;
}
while (a.size() < b.size()) {
int e = b.top();
bs -= e;
b.pop();
a.push(e);
as += e;
}
}
void add(int v) {
if (a.empty() || v < a.top()) {
a.push(v);
as += v;
} else {
b.push(v);
bs += v;
}
resz();
}
ll ans() {
return ((ll) a.top() * a.size()) - as + bs - ((ll) a.top() * b.size());
}
};
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int k, n; cin >> k >> n;
ll ans = 0;
vector<vector<int>> route = {{}};
for (int i = 0; i < n; ++i) {
char ac, bc;
int a, b;
cin >> ac >> a >> bc >> b;
if (ac == bc) {
ans += abs(b - a);
} else {
route.push_back({a + b, a, b});
}
}
n = route.size() - 1;
route.push_back({});
sort(next(route.begin()), prev(route.end()));
vector<ll> pref(n + 1);
pref[0] = 0;
med m1;
for (int i = 1; i <= n; ++i) {
m1.add(route[i][1]);
m1.add(route[i][2]);
pref[i] = m1.ans();
}
vector<ll> suff(n + 2);
suff[n + 1] = 0;
med m2;
for (int i = n; i >= 1; --i) {
m2.add(route[i][1]);
m2.add(route[i][2]);
suff[i] = m2.ans();
}
if (k == 1) {
cout << pref[n] + ans + n << '\n';
} else {
ll best = INT64_MAX;
for (int i = 0; i <= n; ++i) {
best = min(best, pref[i] + suff[i + 1]);
}
cout << best + ans + n << '\n';
}
return 0;
}
