#include <bits/stdc++.h>
using namespace std;
#define int long long
const int inf = 2e18;
signed main(){
ios::sync_with_stdio(0);
cin.tie(nullptr); cout.tie(nullptr);
int n, m, ans = 0;
cin >> n >> m;
char s1, s2;
int x, y;
vector<pair<int, int>> v;
vector<int> alx;
for(int i = 1; i <= m; ++i){
cin >> s1 >> x >> s2 >> y;
if(s1 == s2){
ans += abs(x - y);
}else{
v.push_back({min(x, y), max(x, y)});
alx.push_back(x);
alx.push_back(y);
++ans;
}
}
sort(alx.begin(), alx.end());
int mid = alx[alx.size() / 2];
x = inf;
for(auto it : alx){
int cur = 0;
for(auto p : v){
cur += min(abs(p.first - it) + abs(p.second - it), abs(mid - p.first) + abs(mid - p.second));
}
x = min(cur, x);
}
cout << x + ans << "\n";
return 0;
}
