#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;
#define int long long
signed main(){
int k, n, Ans = 0, Sumr = 0, finalAns = 1e17;
cin>>k>>n;
vector<pair<int,int>> vec;
vector<int> pnt;
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});
pnt.push_back(b);
pnt.push_back(d);
Ans += d - b + 1;
Sumr += b + 1;
}
}
sort(begin(vec), end(vec));
sort(begin(pnt), end(pnt));
finalAns = Ans + Sumr * 2;
if (k == 1){
int Rgt = vec.size(), Lft = 0, Suml = 0, id = 0, lst = -1;
multiset<int> st;
for (int i : pnt){
Sumr -= Rgt * (i - lst);
Suml += Lft * (i - lst);
while (id < vec.size() and vec[id].first == i)
st.insert(vec[id].second), id++, Rgt--;
while (st.size() > 0 and *begin(st) == i)
Lft++, st.erase(begin(st));
// cout<<i<<" | "<<Lft<<" "<<Suml<<" | "<<Rgt<<" "<<Sumr<<endl;
lst = i;
finalAns = min(finalAns, Ans + (Suml + Sumr) * 2);
}
return cout<<finalAns<<endl, 0;
}
}
/*
1 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
*/
