#include "bits/stdc++.h"
#define MAXN 100009
#define INF 1000000007
#define mp(x,y) make_pair(x,y)
#define all(v) v.begin(),v.end()
#define pb(x) push_back(x)
#define wr cout<<"----------------"<<endl;
#define ppb() pop_back()
#define tr(ii,c) for(__typeof((c).begin()) ii=(c).begin();ii!=(c).end();ii++)
#define ff first
#define ss second
#define my_little_dodge 46
#define debug(x) cerr<< #x <<" = "<< x<<endl;
using namespace std;
typedef long long ll;
typedef pair<int,int> PII;
template<class T>bool umin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool umax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
vector<int>can;
vector<PII>v;
ll f(int x){x=can[x];
ll res=0;
tr(it,v)
res+=abs(it->ff-x)+abs(x-it->ss)+1;
return res;
}
ll f1(int x,int y){
ll res=0;
tr(it,v)
res+=min(abs(it->ff-x)+abs(it->ss-x),abs(it->ff-y)+abs(it->ss-y))+1;
return res;
}
int main(){
//~ freopen("file.in", "r", stdin);
int k,n;
scanf("%d%d",&k,&n);
if(k==1){
ll ans=0;
for(int i=1;i<=n;i++){
char a,c;
int b,d;
scanf(" %c%d %c%d",&a,&b,&c,&d);
can.pb(b);can.pb(d);
if(a!=c)
v.pb(mp(b,d));
else
ans+=abs(b-d);
}
sort(all(can));
can.erase(unique(all(can)),can.end());
int st=0,en=can.size()-1;
while(st+1<en){
int mid=(st+en)>>1;
if(f(mid)<f(mid+1))
en=mid;
else
st=mid;
}
printf("%lld\n",ans+min(f(st),f(en)));
}
if(k==2){
ll ans=0;
for(int i=1;i<=n;i++){
char a,c;
int b,d;
scanf(" %c%d %c%d",&a,&b,&c,&d);
can.pb(b);can.pb(d);
if(a!=c)
v.pb(mp(b,d));
else
ans+=abs(b-d);
}
sort(all(can));
can.erase(unique(all(can)),can.end());
ll res=LONG_LONG_MAX;
for(int i=0;i<int(can.size());i++){
int st=i+1,en=can.size()-1;
while(st+100<en){
int mid=(st+en)>>1;
if(f1(can[i],can[mid])<f1(can[i],can[mid+1]))
en=mid;
else
st=mid;
}
for(int j=st;j<=en;j++)
umin(res,ans+f1(can[i],can[j]));
}
printf("%lld\n",res);
}
return 0;
}
