Untitled

def count_tan(x1, x2, y1, y2):
    if x2 - x1 == 0:
        return 10**100
    return (y2 - y1) / (x2 - x1)

n = int(input())
a = []
for i in range(n):
    a.append(list(map(int, input().split())))

tan = []
for i in range(0, len(a)):
    for j in range(i+1, len(a)):
        tg = count_tan(a[i][0], a[j][0], a[i][1], a[j][1])
        tan.append(tg)

print(len(set(tan)) * 2)