import sys

sys.setrecursionlimit(10**6)
int1 = lambda x: int(x)-1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.buffer.readline())
def LI(): return list(map(int, sys.stdin.buffer.readline().split()))
def LI1(): return list(map(int1, sys.stdin.buffer.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def BI(): return sys.stdin.buffer.readline().rstrip()
def SI(): return sys.stdin.buffer.readline().rstrip().decode()
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = 10**16
md = 998244353
# md = 10**9+7

from math import atan2
from bisect import *

n = II()
xy = LLI(n)

rxy = [(atan2(y, x), x, y) for x, y in xy]
rxy.sort(key=lambda x: x[0])
rr = [r for r, x, y in rxy]
# print(rxy)
# print(rr)

ans = 0
for i in range(n):
    r1, x1, y1 = rxy[i]
    if r1 >= 0: break
    s1 = atan2(-y1, -x1)
    l = bisect_right(rr, s1)
    for j in range(i+1, n):
        r2, x2, y2 = rxy[j]
        if x1*y2-y1*x2 == 0: continue
        if x1*y2-y1*x2 < 0: break
        s2 = atan2(-y2, -x2)
        if s2 < 0: r = n
        else: r = bisect_left(rr, s2)
        ans += r-l
        # print(i,j,l,r,ans)

print(ans)