#include <bits/stdc++.h>
using namespace std;
using ll = long long; using pii = pair<ll,ll>;
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
ll K,N; cin >> K >> N;
vector<pii> v;
ll ans = 0;
for (ll i=0;i<N;i++) {
string p,q; ll s,t;
cin >> p >> s >> q >> t;
if (p==q) {
ans += abs(s-t);
} else {
ans++;
v.push_back({min(s,t),max(s,t)});
}
}
vector<ll> v2;
for (pii p0: v) {
v2.push_back(p0.first);
v2.push_back(p0.second);
}
if (K==1) {
sort(v2.begin(),v2.end());
for (ll x: v2) {
ans += abs(x-v2[v2.size()/2]);
}
cout << ans; exit(0);
}
ll emin = 1e18;
for (ll a: v2) {
ll ec = 0;
priority_queue<pii> PQ; //-pos,sign(+1/-1)
for (pii p0: v) {
ll x = p0.first; ll y = p0.second;
ec += abs(a-x)+abs(a-y);
if (a<x || a>y) {
PQ.push({-a,-1});
PQ.push({-x,1});
PQ.push({-y,1});
PQ.push({-x-y+a,-1});
}
}
ll xmin = 1e18;
ll sp=0; ll sn=0;
while (!PQ.empty()) {
pii p0 = PQ.top(); PQ.pop();
ll p = -p0.first; ll n = p0.second;
xmin = min(xmin,(p*sn-sp));
sp += p*n; sn += n;
}
emin = min(emin,2*xmin+ec);
}
cout << (emin+ans);
}
