#include <iostream>
#include <queue>
#include <algorithm>
using namespace std;
#define int long long
const int N = 100005, K = 700;
priority_queue<int> pQ, dm1;
priority_queue<int, vector<int>, greater<int>> Pq, dm2;
int Sum1, Sum2, pre[N];
int insert(int l, int r){
pQ.push(l);
Pq.push(r);
Sum2 += r, Sum1 += l;
while (Pq.top() < pQ.top()){
int k1 = pQ.top(), k2 = Pq.top();
pQ.pop(), Pq.pop();
Sum1 += -k1 + k2, Sum2 += -k2 + k1;
Pq.push(k1), pQ.push(k2);
}
return Sum2 - Sum1;
}
signed main(){
int k, n, Ans = 0, Ans1 = 1e17;
cin>>k>>n;
vector<pair<int,int>> vec;
for (int i=1;i<=n;i++){
char a, c;
int b, d;
cin>>a>>b>>c>>d;
if (b >= d)
swap(b, d);
if (a == c)
Ans += d - b;
else{
vec.push_back({b + d, b});
Ans++;
}
}
sort(begin(vec), end(vec));
n = vec.size();
for (int i=0;i<n;i++)
pre[i] = insert(vec[i].second, vec[i].first - vec[i].second);
if (k == 1)
return cout<<pre[n-1] + Ans<<'\n', 0;
pQ = dm1;
Pq = dm2;
Sum1 = Sum2 = 0;
for (int i=n-1;i>=0;i--)
Ans1 = min(Ans1, Ans + insert(vec[i].second, vec[i].first - vec[i].second) + (i == 0 ? 0 : pre[i-1]));
cout<<Ans1<<endl;
}
