#include <stdio.h>
#include <algorithm>
#include <math.h>

#define MAX_N 1500
#define EPSILON 0.0001

double modul( double a ) {
    return a > 0 ? a : 0;
}

struct punct {
    double x, y;

    bool operator < (const punct &p) const {
        if ( x == p.x )
            return y < p.y;
        return x < p.x;
    }
    bool operator > (const punct &p) const {
        if ( x == p.x )
            return y > p.y;
        return x > p.x;
    }
    bool operator == (const punct &p) const {
        return (modul( x - p.x ) <= EPSILON && modul( y - p.y ) <= EPSILON);
    }
};

double dist2( punct a, punct b ) {
    return ( a.x - b.x ) * ( a.x - b.x ) + ( a.y - b.y ) * ( a.y - b.y );
}


double inaltime[MAX_N];
punct pct[MAX_N];

int main() {
    FILE *fin, *fout;
    int n, echilaterale, egale, i, j;

    fin = fopen( "triang.in", "r" );
    fscanf( fin, "%d", &n );
    for ( i = 0; i < n; i++ )
        fscanf( fin, "%lf%lf", &pct[i].x, &pct[i].y );
    fclose( fin );

    std::sort( pct, pct + n );

    echilaterale = 0;
    for ( i = 0; i < n - 1; i++ ) {
        for ( j = i + 1; j < n; j++ )
            inaltime[j - (i + 1)] = sqrt( 3 * dist2( pct[i], pct[j] ) / 4 );

        std::sort( inaltime, inaltime + n - (i + 1) );

        egale = 0;
        for ( j = 1; i < n - (j + 1); i++ ) {
            if ( modul( inaltime[j] - inaltime[j - 1] ) <= EPSILON )
                egale++;
            else
                egale = 0;
            echilaterale += egale;
        }
    }

    fout = fopen( "triang.out", "w" );
    fprintf( fout, "%d", echilaterale );
    fclose( fout );

    return 0;
}