#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;
#define endl '\n'
#define ll long long
#define pi pair<int, int>
#define f first
#define s second
const int mxn = 100000;
int n, m, k;
pi a[mxn];
ll f[2][mxn];
vector<int> v;
ll sl[2], sr[2];
priority_queue<int> l, ql[2];
priority_queue<int, vector<int>, greater<int>> r, qr[2];
void add(int x, int y){
if(l.empty() || x <= l.top()) l.push(x);
else r.push(x);
while(l.size() < r.size()) l.push(r.top()), r.pop();
while(r.size() + 1 < l.size()) r.push(l.top()), l.pop();
if(x <= l.top()) ql[y].push(x), sl[y] += x;
else qr[y].push(x), sr[y] += x;
for(int t = 0; t < 2; t++){
while(!ql[t].empty() && ql[t].top() > l.top()){
sl[t] -= ql[t].top();
sr[t] += ql[t].top();
qr[t].push(ql[t].top());
ql[t].pop();
}
while(!qr[t].empty() && qr[t].top() <= l.top()){
sr[t] -= qr[t].top();
sl[t] += qr[t].top();
ql[t].push(qr[t].top());
qr[t].pop();
}
}
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
cin >> k >> n;
ll s = 0;
for(int i = 0; i < n; i++){
char c, d;
int x, y;
cin >> c >> x >> d >> y;
if(x > y) swap(x, y);
s += y - x;
if(c != d) s++, a[m++] = {x, y};
}
sort(a, a + m, [&](pi x, pi y){
return x.f + x.s < y.f + y.s;
});
for(int t = 0; t < 2; t++){
while(!l.empty()) l.pop();
while(!r.empty()) r.pop();
for(int i = 0; i < 2; i++){
sl[i] = sr[i] = 0;
while(!ql[i].empty()) ql[i].pop();
while(!qr[i].empty()) qr[i].pop();
}
for(int i = 0; i < m; i++){
add(a[i].f, 0), add(a[i].s, 1);
f[t][i] += sr[0] - (ll)l.top() * qr[0].size();
f[t][i] += (ll)l.top() * ql[1].size() - sl[1];
}
reverse(a, a + m);
}
reverse(f[1], f[1] + m);
ll ret = !!m * 0x3f3f3f3f3f3f3f3f;
if(k & 1) ret = f[1][0];
else for(int i = 1; i < m; i++) ret = min(ret, f[0][i - 1] + f[1][i]);
ret = 2 * ret + s;
cout << ret << endl;
return 0;
}
