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 os, sys
n_pts = int(sys.stdin.readline())
points = []
for k in range(n_pts):
    arr = sys.stdin.readline().split()
    points.append((int(arr[0]), int(arr[1])))

slopedict = dict()

for i1 in range(n_pts):
#    print i1
    for i2 in range(i1+1, n_pts):
#        print i1, i2
        # Compute Abs Slope Between Them
        pt1 = points[i1]
        pt2 = points[i2]
        # choose left most
        if pt1[0] > pt2[0]:
            tmp = pt1
            pt1 = pt2
            pt2 = tmp
        rise = pt2[1] - pt1[1]
        run = pt2[0] - pt1[0]
        dist = rise * rise + run * run
        if run == 0:
            slope = None
        else:
            slope = float(rise)/run # absolute value
        if not slopedict.has_key((slope, dist)):
            slopedict[(slope, dist)] = []
        slopedict[(slope, dist)].append((pt1, pt2))

# For every slope, group together
from operator import mul    # or mul=lambda x,y:x*y
nCk = lambda n,k: int(round(reduce(mul, (float(n-i)/(i+1) for i in range(k)), 1)))

finalsum = 0
for aslope in slopedict:
    clusters = []
    for anedge in slopedict[aslope]:
        edge0find = [x for x in range(len(clusters)) if anedge[0] in clusters[x]]
        edge1find = [x for x in range(len(clusters)) if anedge[1] in clusters[x]]
        if len(edge0find) == 0 and len(edge1find) == 1:
            clusters[edge1find[0]].append(anedge[0])         
            continue
        if len(edge0find) == 1 and len(edge1find) == 0:
            clusters[edge0find[0]].append(anedge[1])         
            continue
        assert not(len(edge0find) == 1 and len(edge1find) == 0)
        if len(edge0find) == 0 and len(edge1find) == 0:
            tmpcluster = []
            tmpcluster.append(anedge[0])
            tmpcluster.append(anedge[1])
            clusters.append(tmpcluster)
            continue
#    print aslope, clusters
    finalsum += sum([nCk(len(x),3) for x in clusters])

print finalsum
