#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define mp make_pair
using namespace std;
const int maxn = 100100;
ll s[maxn], f[maxn], n, k;
char szone[maxn], fzone[maxn];
int main() {
cin>>k>>n;
ll result = 0LL;
vector<ll>v;
vector<pair<ll,ll> > vv;
for(int i=1;i<=n;i++) {
cin>>szone[i]>>s[i];
cin>>fzone[i]>>f[i];
if(szone[i] == fzone[i]) result += abs(f[i] - s[i]);
if(szone[i] != fzone[i]) {
v.pb(s[i]);
v.pb(f[i]);
}
if(s[i] > f[i]) swap(s[i], f[i]);
}
if(v.size() == 0) {
cout<<result;
return 0;
}
if(k == 1) {
ll mintemp = LLONG_MAX;
sort(v.begin(), v.end());
// 0 1 2 3
int half = v[0];
if(v.size() > 1)
half = v[v.size()/2-1];
else half = v.back();
for(int d=half-1;d<=half+1;d++) {
ll temp = 0LL;
for(int i=1;i<=n;i++) {
if(szone[i] != fzone[i]) {
temp += abs(f[i] - d) + abs(s[i] - d) + 1;
}
}
//cout<<d<<": "<<temp<<"\n";
mintemp = min(mintemp, temp);
}
result += mintemp;
cout<<result<<"\n";
return 0;
}
else if(k == 2) {
sort(v.begin(), v.end());
ll mintemp = LLONG_MAX;
for(int i:v) {
vector<int>v2;
ll temp = 0LL;
for(int j=1;j<=n;j++) {
if(fzone[j] == szone[j]) continue;
if(!(s[j] <= i && i <= f[j])) {
v2.pb(s[j]);
v2.pb(f[j]);
}
else {
temp += abs(s[j] - i) + abs(f[j] - i);
}
}
/*cout<<i<<": \n";
for(int i:v2) {
cout<<i<<" ";
} cout<<" - "<<temp<<" -> ";*/
sort(v2.begin(), v2.end());
if(v2.size() == 0) continue;
int half = v2[0];
if(v2.size() > 1)
half = v2[v2.size()/2-1] ;
else half = v2.back();
for(int j:v2) {
temp += abs(j - half);
}
temp += v.size() / 2;
//cout<<temp<<"\n";
mintemp = min(mintemp, temp);
}
cout<<result+mintemp;
}
return 0;
}
