N = input()
s = set()
ans = 0
shuuhen = [(i, j) for i in xrange(-20, 21) for j in xrange(-20, 21) if i*i+j*j<400]
for i in xrange(N):
    x, y = map(int, raw_input().split())
    for j, k in shuuhen:
        if (x+j, y+k) in s:
            print x+j, y+k
            break
    else:
        s.add((x, y))
        ans += 1
print ans