#include <cstdio>
#include <cmath>
#include <algorithm>
using namespace std;
double v[1005], PI= 3.14;
int main()
{
    freopen("trapez.in","r",stdin);
    freopen("trapez.out","w",stdout);
    int n , i , cnt, a , b , t = 0 ;
    scanf("%d",&n);
    for(i=1;i<=n;i++)
    {
        scanf("%d%d",&a,&b);
        v[i]=atan2(b,a);
        if(v[i]<0)
            v[i]+=2*PI;
    }
    sort(v+1,v+n+1);
    cnt = 0 ;
    for(i=1;i<n;i++)
    {
        if(v[i]==v[i+1])
            cnt++;
        else
        {
            t += cnt*(cnt+1)/2;
            cnt = 0 ;
        }
    }
    t+=cnt*(cnt+1)/2;
    printf("%d",t);
    return 0;
}