#include<bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int, int>
int n,k, res;
struct F{
priority_queue<int> L;
priority_queue<int> R;
int opti =0;
int insert(int v){
int ans =0;
if(v>opti){
R.push(-v);
R.push(-v);
ans = (abs(-v - (R.top())));
L.push(-R.top());
R.pop();
}
else{
L.push(v);
L.push(v);
ans = (abs(v - (L.top())));
R.push(-L.top());
L.pop();
}
opti = L.top();
return ans;
}
};
signed main(){
cin>>n>>k;
vector<pii> inters;
for(int i = 0; i<k; i++){
char a, b;
int pa, pb;
cin>>a>>pa>>b>>pb;
if(pa>pb){
swap(pa, pb);
}
////cout<<a<<" "<<b<<endl;
if(a!=b){
inters.push_back(pii(pa, pb));
}
else{
res += abs(pb-pa);
}
}
////cout<<"done "<<inters.size()<<endl;
auto cmp =[&](pii& a, pii& b){
return a.first+a.second<b.first+b.second;
};
sort(inters.begin(), inters.end(), cmp);
int p = inters.size();
vector<pii> scores(p+1, pii(0, 0));
F Lf;
int s= 0;
for(int i = 0; i<p; i++){
s+= Lf.insert(inters[i].first) + Lf.insert(inters[i].second);
scores[i].first = s;
}
////cout<<"right "<<endl;
F Rf;
s= 0LL;
for(int i = p-1; i>=0; i--){
s += Rf.insert(inters[i].first) + Rf.insert(inters[i].second);
scores[i].second = s;
}
int cost_cross= 1e18;
for(int i = 0; i<p; i++){
//cout<<scores[i].first<<" "<<scores[i].second<<endl;
cost_cross = min(cost_cross, scores[i].first + scores[i+1].second);
}
res+=p;
if(p==0){
cout<<res<<endl;
}
else if(n==2){
cout<<res+cost_cross<<endl;
}
else{
cout<<scores[p-1].first +res<<endl;
}
}
