#include <cstdio>

using namespace std;

long long x[1001],y[1001],n,nr=0;

int main(){
	
	freopen("trapez.in","r",stdin);
	scanf("%ld",&n);
	
	for (int i=0;i<n;i++){
		scanf("%ld %ld",&x[i],&y[i]);
	}

	fclose(stdin);

	for (int i=0;i<n-3;i++){
		for(int j=i+1;j<n-2;j++){
			for(int k=j+1;k<n-1;k++){
				for(int l=k+1;l<n;l++){

					if((x[i]==x[j])&&(x[k]==x[l]))nr++;
					else if((x[i]==x[k])&&(x[j]==x[l]))nr++;
					else if((x[i]==x[l])&&(x[k]==x[j]))nr++;
					
					if((y[i]==y[j])&&(y[k]==y[l]))nr++;
					else if((y[i]==y[k])&&(y[j]==y[l]))nr++;
					else if((y[i]==y[l])&&(y[k]==y[j]))nr++;
				}
			}
		}
	}
	
	freopen("trapez.out","w",stdout);
	printf("%ld",nr);
	fclose(stdout);
	
	return 0;
}