#include<bits/stdc++.h>
#define MAXN 100007
using namespace std;
const long long inf=1e17;
struct house{
int x,y;
};
int n,k,x,y,m,p,q;
long long ans,toadd;
char s,t;
house h[MAXN];
vector<int> vals;
void solve_easy(){
if(m==0){
cout<<ans<<"\n";
return;
}
int pos=vals[m];
for(int i=1;i<=m;i++){
ans+=abs(pos-h[i].x);
ans+=abs(pos-h[i].y);
ans++;
}
cout<<ans<<"\n";
}
long long calc(){
long long sum=0;
for(int i=1;i<=m;i++){
sum+=min( abs(h[i].x-p)+abs(h[i].y-p) , abs(h[i].x-q)+abs(h[i].y-q) )+1;
}
return sum;
}
void solve(int l,int r,int optl,int optr){
if(l>r)return;
int mid=(l+r)/2,opt;
p=vals[mid];
long long best=inf;
for(int i=optl;i<=optr;i++){
q=vals[i];
long long curr=calc();
if(curr<best){
best=curr; opt=i;
}
}
toadd=min(toadd,best);
solve(l,mid-1,optl,opt);
solve(mid+1,r,opt,optr);
}
void solve_hard(){
if(m==0){
cout<<ans<<"\n";
return;
}
vals.erase( unique( vals.begin(), vals.end() ), vals.end() );
sort(vals.begin(),vals.end());
toadd=inf;
solve(0,int(vals.size())-1,0,int(vals.size())-1);
ans+=toadd;
cout<<ans<<"\n";
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin>>k>>n;
for(int i=1;i<=n;i++){
cin>>s>>x>>t>>y;
if(s==t){
ans+=abs(x-y);
continue;
}
m++; h[m]={x,y};
}
for(int i=1;i<=m;i++){
vals.push_back(h[i].x);
vals.push_back(h[i].y);
}
sort(vals.begin(),vals.end());
if(k==1){
solve_easy();
}else{
solve_hard();
}
return 0;
}
