#include <bits/stdc++.h>
#define int long long
#define pii pair<int,int>
#define pb push_back
#define all(x) x.begin(),x.end()
#define endl "\n"
using namespace std;
vector<pii> p;
int solve(int ini, int fin) {
vector<int> x(0);
for(int i=ini; i<fin; ++i) {
auto &[a,b] = p[i];
x.pb(a), x.pb(b);
}
sort(all(x));
int mid=x[fin-ini], ans=0;
for(int &y : x) ans+=abs(y-mid);
return ans;
}
const int inf=0x3f3f3f3f;
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int k, n;
cin >> k >> n;
int ans=0;
for(int i=0; i<n; ++i) {
char st, ed;
int l, r;
cin >> st >> l >> ed >> r;
if(st==ed) ans += abs(r-l);
else {
p.pb({l,r});
ans++;
}
}
sort(all(p));
if(k==1) ans+=solve(0,p.size());
else {
int aux=inf;
for(int mid=1; mid<p.size(); ++mid) {
aux = min(aux, solve(0,mid)+solve(mid,p.size()));
}
if(aux!=inf) ans+=aux;
}
cout << ans << endl;
}
