#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for (int i=a; i<int(b); i++)
#define all(x) x.begin(),x.end()
vector<pair<long long,long long> > travels;
long long cost(long long point) {
long long ans=0;
for (auto a:travels) {
long long c,d;
c=a.first;
d=a.second;
ans += abs(point-c);
ans += abs(point-d);
ans += 1;
/*assert (c<=d);
ans+=abs(d-c);
ans++;
if (point >d) ans+=2*(point-d);
if (point<c) ans+=2*(c-point);
*/
}
return ans;
}
int main() {
int n,k;
cin >> k >> n;
long long sum=0;
vector<long long> points;
rep (i,0,n) {
char a,b;
long long c,d;
cin >> a >> c >> b >> d;
if (a==b) sum+=abs(c-d);
else {
travels.push_back(make_pair(c,d));
points.push_back(c);
points.push_back(d);
}
}
long long best=1000000000000;
rep (i,0,points.size()) {
best=min(best,cost(points[i]));
}
if (best == 1000000000000) best=0;
cout << best+sum << endl;
}
