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

import sys

def main():
    all_input = iter(sys.stdin.read().strip().replace('\n', ' ').split(' '))
    n = int(all_input.next())

    pts = []
    pts_hash = {}
    for i in xrange(n):
        x = int(all_input.next())
        y = int(all_input.next())
        pts.append((x, y))
        try:
            pts_hash[x].append(y)
        except KeyError:
            pts_hash[x] = [y]

    # qt = 0
    count = set()
    for i in xrange(n):
        for j in xrange(i+1, n):
            deltax = pts[j][0] - pts[i][0]
            deltay = pts[j][1] - pts[i][1]
            try:
                if pts[j][1]+deltay in pts_hash[pts[j][0]+deltax]:
                    aux = [pts[i], pts[j], (pts[j][0]+deltax, pts[j][1]+deltay)]
                    aux.sort(key=lambda x: x[0]+x[1])
                    count.add(str(aux))
                    # count.add(set([pts[i], pts[j], (pts[j][0]+deltax, pts[j][1]+deltay)]))
                    # print pts[i], pts[j]
                    # qt += 1
            except KeyError:
                pass
            # print i, j

    # print pts
    # print pts_hash
    print len(count)

if __name__ == '__main__':
    main()