#include<bits/stdc++.h>
#pragma GCC optimize("unroll-loops,no-stack-protector,Ofast")
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
const ll MOD=1e9+7;
const ll MOD2=998244353;
const ll N=2e5+5;
const ld pi=acos(-1);
const ll INF=(1LL<<60);
#define SQ(i) ((i)*(i))
#define REP(i,n) for(ll i=0;i<n;i++)
#define REP1(i,n) for(ll i=1;i<=n;i++)
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define setp setprecision
#define lwb lower_bound
#define SZ(_a) (ll)_a.size()
priority_queue<ll> pqa;
priority_queue<ll,vector<ll>,greater<ll> > pqb;
ll k,n,sum,x,y,ans,suf[N],pre[N];
char A,B;
vector<pll> v;
void add(ll d){
if(SZ(pqa)&&d<pqa.top())sum-=d,pqa.push(d);
else sum+=d,pqb.push(d);
while(SZ(pqa)>SZ(pqb)){
d=pqa.top();pqa.pop();pqb.push(d);
sum+=d*2;
}
while(SZ(pqb)>SZ(pqa)+1){
d=pqb.top();pqb.pop();pqa.push(d);
sum-=d*2;
}
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);
cin>>k>>n;
REP1(i,n){
cin>>A>>x>>B>>y;
if(A==B){ans+=abs(x-y);continue;}
++ans;
v.pb(mp(x+y,y));
}
sort(v.begin(),v.end());
n=SZ(v);
if(n==0){cout<<ans<<"\n";return 0;}
while(SZ(pqa))pqa.pop();
while(SZ(pqb))pqb.pop();
sum=0;
REP(i,n){
add(v[i].X-v[i].Y);
add(v[i].Y);
//cout<<sum<<" "<<pqb.top()<<" "<<SZ(pqa)-SZ(pqb)<<"\n";
pre[i]=sum;
}
while(SZ(pqa))pqa.pop();
while(SZ(pqb))pqb.pop();
sum=0;
for(int i=n-1;i>=0;i--){
add(v[i].X-v[i].Y);
add(v[i].Y);
suf[i]=sum;
}
//cout<<pre[n-1]<<"\n";
ll tans=ans+pre[n-1];
if(k==2){
for(int i=0;i+1<n;i++)tans=min(tans,ans+pre[i]+suf[i+1]);
}
cout<<tans<<"\n";
return 0;
}
/*
1 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
*/
