#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;
#define int long long
int get(vector<pair<int,int>> vc, int l, int r, int Ans = 0){
for (int i=0;i<vc.size();i++){
if (vc[i].second <= l)
Ans += (l - vc[i].second);
else if (vc[i].first >= r)
Ans += (vc[i].first - r);
else if (l <= vc[i].first and r >= vc[i].second)
Ans += min(vc[i].first - l,r - vc[i].second);
}
return Ans * 2;
}
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));
pnt.resize(unique(begin(pnt), end(pnt)) - begin(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;
}
for (int l=0, r=0;l<pnt.size();l++){
int cur = get(vec, pnt[l], pnt[r]);
while (r + 1 < pnt.size()){
int Nw = get(vec, pnt[l], pnt[r + 1]);
if (Nw <= cur)
cur = Nw, r++;
else
break;
}
finalAns = min(finalAns, cur + Ans);
// cout<<l<<" "<<r<<" "<<cur<<endl;
}
cout<<finalAns<<'\n';
}
