#include <bits/stdc++.h>
#define f first
#define s second
#define pb push_back
#define vec vector
#define sz(x) (int)(x).size()
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define pw(x) (1LL<<(x))
#define fast_iati ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
template <class T> bool umin(T &a,const T &b){return (a>b?a=b,1:0);}
template <class T> bool umax(T &a,const T &b){return (a<b?a=b,1:0);}
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const ll inf=1e18;
signed main(){
fast_iati;
int k,n;
cin>>k>>n;
vec<int>l,r;
ll ans=0;
vec<int>kek;
for(int i=0;i<n;i++){
char f,s;
int x,y;
cin>>f>>x>>s>>y;
if(f==s) ans+=abs(x-y);
else{
if(x>y) swap(x,y);
l.pb(x);r.pb(y);
}
}
n=sz(l);
for(int i=0;i<n;i++){
kek.pb(l[i]);
kek.pb(r[i]);
}
sort(all(kek));kek.erase(unique(all(kek)),kek.end());
if(k==1){
if(!sz(kek)){
cout<<ans;
return 0;
}
auto f=[&](int i){
int x=kek[i];
ll me=0;
for(int k=0;k<n;k++){
me+=abs(x-l[k])+abs(x-r[k])+1;
}
return me;
};
int tl=0,tr=sz(kek)-1;
while(tr-tl>=3){
int t1=tl+(tr-tl)/3;
int t2=tr-(tr-tl)/3;
if(f(t1)<f(t2)) tr=t2;
else tl=t1;
}
ll mn=inf;
for(int i=tl;i<=tr;i++)
umin(mn,f(i));
cout<<ans+mn;
}
else{
if(!sz(kek)){
cout<<ans;
return 0;
}
auto f1=[&](int i,int j){
int x=kek[i],y=kek[j];
ll me=0;
for(int k=0;k<n;k++){
me+=min(abs(y-l[k])+abs(y-r[k]),abs(x-l[k])+abs(x-r[k]))+1;
}
return me;
};
auto f=[&](int i){
int tl=0,tr=sz(kek)-1;
while(tr-tl>=10){
int t1=tl+(tr-tl)/3;
int t2=tr-(tr-tl)/3;
if(f1(i,t1)<f1(i,t2)) tr=t2;
else tl=t1;
}
ll mn=inf;
for(int j=tl;j<=tr;j++) umin(mn,f1(i,j));
return mn;
};
int tl=0,tr=sz(kek)-1;
while(tr-tl>=10){
int t1=tl+(tr-tl)/3;
int t2=tr-(tr-tl)/3;
if(f(t1)<f(t2)) tr=t2;
else tl=t1;
}
ll mn=inf;
for(int i=tl;i<=tr;i++)
umin(mn,f(i));
cout<<ans+mn;
}
return 0;
}
/*
2 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
*/
