#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define fi first
#define se second
const int mxN=1e5;
int k, n, pts[2*mxN], med, ft2[2*mxN+1];
ll ba, ft1[2*mxN+1], a1[mxN+1], a2=LLONG_MAX;
vector<pii> ps;
priority_queue<int> bpq;
priority_queue<int, vector<int>, greater<int>> tpq;
inline void upd(int x) {
if(x<med)
bpq.push(x);
else
tpq.push(x);
if(bpq.size()+2<=tpq.size()) {
bpq.push(med);
med=tpq.top(), tpq.pop();
} else if(bpq.size()>=tpq.size()+2) {
tpq.push(med);
med=bpq.top(), bpq.pop();
}
for(int i=upper_bound(pts, pts+2*ps.size(), x)-pts; i<=2*ps.size(); i+=i&-i)
ft1[i]+=x, ++ft2[i];
}
inline ll qry1(int x) {
ll r=0;
for(int i=upper_bound(pts, pts+2*ps.size(), x)-pts; i; i-=i&-i)
r+=ft1[i];
return r;
}
inline int qry2(int x) {
int r=0;
for(int i=upper_bound(pts, pts+2*ps.size(), x)-pts; i; i-=i&-i)
r+=ft2[i];
return r;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> k >> n;
for(int i=0; i<n; ++i) {
char z1, z2;
pii pi;
cin >> z1 >> pi.fi >> z2 >> pi.se;
if(z1!=z2) {
pts[2*ps.size()]=pi.fi, pts[2*ps.size()+1]=pi.se;
ps.push_back(pi);
++ba;
} else
ba+=abs(pi.fi-pi.se);
}
sort(pts, pts+2*ps.size());
sort(ps.begin(), ps.end(), [](const pii &a, const pii &b) {
return a.fi+a.se<b.fi+b.se;
});
// cout << "hi1" << endl;
for(int i=0; i<ps.size(); ++i) {
upd(ps[i].fi), upd(ps[i].se);
a1[i+1]=(qry1(pts[2*ps.size()-1])-2*qry1(med))-(ll)med*(qry2(pts[2*ps.size()-1])-2*qry2(med));
}
// cout << "hi2" << endl;
if(k==1) {
// cout << ba+a1[3] << endl;
cout << ba+a1[ps.size()];
return 0;
}
memset(ft1, 0, 8*(2*ps.size()+1));
memset(ft2, 0, 4*(2*ps.size()+1));
// cout << "hi3" << endl;
bpq=priority_queue<int>(), tpq=priority_queue<int, vector<int>, greater<int>>();
// cout << "hi4" << endl;
for(int i=ps.size()-1; i; --i) {
upd(ps[i].fi), upd(ps[i].se);
a2=min(a1[i]+(qry1(pts[2*ps.size()-1])-2*qry1(med))-(ll)med*(qry2(pts[2*ps.size()-1])-2*qry2(med)), a2);
}
cout << ba+a2;
}
