[백준/파이썬]4641번 Doubles

-코드

while 1:
    s = list(map(int, input().split()))
    r = 0
    if s[0] == -1:
        break
    for i in range(len(s) - 1):
        for j in range(len(s) - 1):
            if s[i] * 2 == s[j]:
                r += 1

    print(r)