from bisect import *
from math import *
import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]

def main():
    n=int(input())
    xy=[LI() for _ in range(n)]
    rad=[atan2(y,x) for x,y in xy]
    #print(rad)
    rad.sort()
    #rad+=[r+2*pi for r in rad]
    #print(rad)
    ans=0
    for i in range(n-2):
        r0=rad[i]
        if r0>pi:break
        L=bisect_right(rad,r0+pi)
        for j in range(i+1,n-1):
            r1=rad[j]
            if r0+pi<=r1:break
            R=bisect_left(rad,r1+pi)
            #print(i,j,r0,r1,L,R)
            ans+=R-L
    print(ans)

main()