#include <bits/stdc++.h>
using namespace std;
const int nx=1e5+5;
#define ll long long
ll k, n, b[nx], d[nx], cnt, res, dpl[nx], dpr[nx], sml, smr;
char a[nx], c[nx];
vector<pair<ll, ll>> v(nx);
priority_queue<ll> pql;
priority_queue<ll, vector<ll>, greater<ll>> pqr;
void insert(int x)
{
if (pql.empty()||(x<=pql.top())) pql.push(x), sml+=x;
else pqr.push(x), smr+=x;
}
void adjust()
{
while (pql.size()>pqr.size()) sml-=pql.top(), pqr.push(pql.top()), pql.pop(), smr+=pqr.top();
while (pqr.size()>pql.size()) smr-=pqr.top(), pql.push(pqr.top()), pqr.pop(), sml+=pql.top();
}
int main()
{
cin.tie(NULL)->sync_with_stdio(false);
cin>>k>>n;
for (int i=1; i<=n; i++)
{
cin>>a[i]>>b[i]>>c[i]>>d[i];
if (a[i]==c[i]) res+=abs(b[i]-d[i]);
else res++, v[++cnt]={b[i]+d[i], i};
}
sort(v.begin()+1, v.begin()+cnt+1);
//for (int i=1; i<=cnt; i++) cout<<v[i].first<<' '<<v[i].second<<'\n';
for (int i=1; i<=cnt; i++)
{
insert(b[v[i].second]);
insert(d[v[i].second]);
adjust();
dpl[i]=smr-sml;
//cout<<"debug "<<sml<<' '<<smr<<'\n';
//cout<<"dp "<<i<<' '<<dpl[i]<<'\n';
}
cout<<dpl[cnt]+res;
}
