#include<bits/stdc++.h>
using namespace std;
long long been_used[2000010]={0};
typedef struct road{
	long long x,y,k,v;
}road;
bool cmp(road p,road q){
	return p.v>q.v;
}
int main(){
	int n;
	cin>>n;
	road a[n+1];
	for(int i=0;i<n;i++){
		cin>>a[i].x>>a[i].y>>a[i].k>>a[i].v;
	}
	sort(a,a+n,cmp);
	int ans=0,sum=a[0].v;
	been_used[a[0].k+100005]=a[0].v;
	for(int i=1;i<n;i++){
		ans+=sum;
		sum+=a[i].v;
		//cout<<ans<<" "<<sum<<endl;
		if(been_used[a[i].k+100005]){
			
			ans-=been_used[a[i].k+100005];
	    }
		been_used[a[i].k+100005]+=a[i].v;
	}
	cout<<ans;
	return 0;
}