10
-2 1
2 -2
-1 -2
0 0
2 -1
0 -2
2 2
0 2
-1 -1
1 -2
 40
-8 24
2 -1
1 -18
72 -70
5 -4
-308 436
-19 40
36 -35
-178 265
-1 2
-7 30
-1 0
3 -2
200 -285
17 -16
-35 74
0 -4
-86 106
-1 4
-7 6
0 1
-5 4
-2 3
6 -5
-4 5
181 -262
76 -118
0 0
-7 18
-58 104
-5 6
-6 12
-3 4
1 0
11 -10
-86 130
-3 6
153 -236
-183 270
-33 64
 5
0 -1
0 -2
0 -3
0 -4
0 -5
 10
0 1
-1 -1
1 1
-1 0
1 -1
-2 -1
-2 2
-2 0
0 -2
0 -1
 20
-1 18
-2 5
-5 4
2 -33
9 -18
0 0
11 -22
2 0
-1 2
-4 41
1 6
1 -2
6 -12
0 1
-3 6
3 -6
3 -8
-1 4
2 -5
1 0
 10
2 1
-1 0
-2 -1
-1 1
0 2
2 -2
0 0
-2 -2
0 -2
-2 1
 20
-3 -3
0 4
-3 1
1 1
-1 2
-4 4
3 -1
-3 0
0 2
4 0
2 3
2 4
4 -3
-4 3
-1 1
1 3
-2 4
1 -2
1 -1
3 0
 3
0 0
0 -1
0 1
 10
2 1
-1 1
0 0
-3 1
-2 -3
-1 -2
-1 -1
1 2
3 -2
0 -2
 3
3 3
1 2
1 1
 4
0 0
1 0
2 0
3 0
 9
1 1
1 0
0 1
0 0
-1 0
-1 1
-1 -1
1 -1
0 -1
 7
1 1
-1 -1
1 0
0 1
-1 0
0 -1
0 0

4
 57
 4
 5
 21
 4
 10
 1
 1
 0
 2
 8
 3


/*
u33how
*/

#include<bits/stdc++.h>
using namespace std ;

int n ;
int x , y ;
int x1 , y1 , x2 , y2 , mx , my ;
vector< pair<int,int> > points ;
set< pair<int,int> > myset ;

int main()
{
    //freopen("input.txt","r",stdin) ;
    ios_base::sync_with_stdio(false) ;
    cin.tie(0) ;

    cin >> n ;
    for( int i = 0 ; i < n ; i++ )
        cin >> x >> y , points.push_back({x,y}) , myset.insert({x,y}) ;

    sort(points.begin(),points.end()) ;
    int ans = 0 ;
    for( int i = 0 ; i < n ; i++ )
    {
        x1 = points[i].first ;
        y1 = points[i].second ;

        for( int j = i+1 ; j < n ; j++ )
        {
            x2 = points[j].first ;
            y2 = points[j].second ;

            if( x1%2 == x2%2 && y1%2 == y2%2 )
            {
                mx = (x1+x2)/2 ;
                my = (y1+y2)/2 ;
                if( myset.find({mx,my}) != myset.end() ) ans++ ;
            }
        }
    }
    cout << ans << endl ;
    return 0 ;

}
