from fractions import Fraction
import sys
input = sys.stdin.readline

n=int(input())
P=[tuple(map(int,input().split())) for i in range(n)]

Q=[]

for x,y in P:
    if x>0:
        Q.append((1,Fraction(y,x)))
    elif x==0:
        if y>0:
            Q.append((1,float("inf")))
        else:
            Q.append((0,float("inf")))

    else:
        Q.append((0,Fraction(y,x)))
        
#print(Q)

Q.sort()

ANS=0
import bisect

for i in range(n-1):
    for j in range(i+1,n):

        if Q[i][0]==Q[j][0]:
            x=bisect.bisect_right(Q,(1-Q[i][0],Q[i][1]))
            y=bisect.bisect_left(Q,(1-Q[j][0],Q[j][1]))

            #print(i,j,x,y)
            ANS+=max(0,y-x)

        else:
            break
        
print(ANS)