#include <cstdio>
#include <set>
#include <algorithm>
using namespace std;
pair<int,int> ei[100100];
long long tmp[100100];
template <typename T,typename U>
long long work(T first, T last, U op) {
op(first,0);
multiset<int> ms;
multiset<int>::iterator mid;
ms.insert(first->first);
ms.insert(first->second);
mid = ms.begin();
long long sum=first->second-first->first;
op(++first,sum);
while (first!=last) {
ms.insert(first->first);
ms.insert(first->second);
sum+=abs(*mid-first->first);
sum+=abs(*mid-first->second);
if (first->second<*mid) {
mid--;
} else if (first->first>=*mid) {
sum+=*mid*2;
mid++;
sum-=*mid*2;
}
op(++first,sum);
}
return sum;
}
int main () {
int k,n;
scanf("%d%d",&k,&n);
char a,b;
int x,y;
long long ans=0;
int sz=0;
for (int i=0;i<n;i++) {
scanf(" %c%d %c%d",&a,&x,&b,&y);
if (a==b) {
ans+=abs(x-y);
} else {
ans+=1;
ei[sz++]=minmax(x,y);
}
}
sort(ei,ei+sz,[](const pair<int,int> &a, const pair<int,int> &b) {
return a.first+a.second<b.first+b.second;
});
if (sz) {
if (k==1) {
ans+=work(ei,ei+sz,[](pair<int,int> *a, long long b) {});
} else {
work(ei,ei+sz,[](pair<int,int> *a,long long b) {
tmp[a-ei]=b;
});
using R=reverse_iterator<pair<int,int>*>;
work(R(ei+sz),R(ei),[](R a, long long b) {
tmp[a.base()-ei]+=b;
});
ans+=*min_element(tmp,tmp+sz);
}
}
printf("%lld\n",ans);
return 0;
}
