#誤差ゲーで余りにも虚無なので多分そもそもの解法が間違っている.
import math
import bisect

tiny = 0.00000001

n = int(input())
a = []
for i in range(n):
    x, y = map(float, input().split())
    tmp = math.atan2(y, x)
    if tmp < 0 : tmp = 2*math.pi+tmp
    a.append(tmp / math.pi * 180)
a.sort()
print(a)
ans = 0
for i in range(n):
    for j in range(i+1, n):
        if abs(a[i]-a[j])<tiny or abs(abs(a[i]-a[j])-180)<tiny : continue
        diff = min(a[j]-a[i], 360-(a[j]-a[i]))
        f = a[i]+180
        g = a[j]+180
        if f < 360 and g < 360 :
            ans += bisect.bisect_left(a,g)-bisect.bisect_right(a,f)
        elif f < 360 and g >= 360 :
            g -= 360;
            if abs(g+360-f-diff) < tiny:
                ans += n - bisect.bisect_right(a,f)
                ans += bisect.bisect_left(a,g)
            else:
                f,g = g,f
                ans += bisect.bisect_left(a,g)-bisect.bisect_right(a,f)
        elif f >= 360 and g >= 360:
            f -= 360
            g -= 360
            ans += bisect.bisect_left(a,g)-bisect.bisect_right(a,f)
print(ans//3)