#include<bits/stdc++.h>
#define MAX_N 100005
#define inf (1LL<<60)
#define pb push_back
#define fi first
#define se second
using namespace std;
typedef long long LL;
typedef pair<LL,LL> pil;
struct node{
LL cnt,sum;
node *l,*r;
node(LL cnt,LL sum,node *l,node *r):cnt(cnt),sum(sum),l(l),r(r){}
node *update(LL idx,LL p,LL val,LL x){
if(idx<0) return new node(cnt+x,sum+x*val,NULL,NULL);
if(p>>idx&(1LL)) return new node(cnt+x,sum+x*val,l,r->update(idx-1,p,val,x));
return new node(cnt+x,sum+x*val,l->update(idx-1,p,val,x),r);
}
}*R1,*R2;
LL n,k,m;
LL ans,aa;
vector<LL> X;
pil arr[MAX_N];
pil serch(LL idx,node *x,LL cnt,LL p){
if(idx<0) return {X[p],X[p]*cnt};
if(x->l->cnt<cnt){
pil q=serch(idx-1,x->r,cnt-x->l->cnt,(p|(1LL<<idx)));
q.se+=x->l->sum;
return q;
}
return serch(idx-1,x->l,cnt,p);
}
LL read(node *RX){
pil p=serch(19,RX,RX->cnt/2,0);
return (RX->cnt/2)*p.fi-p.se+(RX->sum-p.se)-(RX->cnt-RX->cnt/2)*p.fi;
}
int main(){
LL i,x;
char a[5],b[5];
scanf("%lld %lld",&k,&n);
for(i=1;i<=n;i++){
scanf("%s %lld %s %lld",a,&arr[m].fi,b,&arr[m].se);
if(a[0]==b[0]){
aa+=abs(arr[m].fi-arr[m].se);
continue;
}
X.pb(arr[m].fi);X.pb(arr[m].se);
m++;
aa++;
}
sort(X.begin(),X.end());X.erase(unique(X.begin(),X.end()),X.end());
sort(arr,arr+m,[&](const pil x,const pil y){
return x.fi+x.se<y.fi+y.se;
});
R1=new node(0,0,NULL,NULL);R1->l=R1->r=R1;
R2=new node(0,0,NULL,NULL);R2->l=R2->r=R2;
for(i=0;i<m;i++){
R2=R2->update(19,(lower_bound(X.begin(),X.end(),arr[i].fi)-X.begin()),arr[i].fi,1);
R2=R2->update(19,(lower_bound(X.begin(),X.end(),arr[i].se)-X.begin()),arr[i].se,1);
}
ans=read(R2);
if(k==1) return !printf("%lld\n",aa+ans);
for(i=0;i<m;i++){
R1=R1->update(19,(lower_bound(X.begin(),X.end(),arr[i].fi)-X.begin()),arr[i].fi,1);
R1=R1->update(19,(lower_bound(X.begin(),X.end(),arr[i].se)-X.begin()),arr[i].se,1);
R2=R2->update(19,(lower_bound(X.begin(),X.end(),arr[i].fi)-X.begin()),arr[i].fi,-1);
R2=R2->update(19,(lower_bound(X.begin(),X.end(),arr[i].se)-X.begin()),arr[i].se,-1);
x=read(R1)+read(R2);
ans=min(ans,x);
}
printf("%lld\n",aa+ans);
return 0;
}
