from typing import List

def main():
    vi = list(map(int, input().split()))
    vi.sort()
    maxV = vi[-1]

    r = float('inf')
    for a in range(1, maxV + 1):
        for b in range(a, maxV + 1):
            for c in range(b, maxV + 1):
                d = calc(vi, [a, b, c])
                if d > 0:
                    r = min(r, d)

    print(r)

def calc(vi: List[int], ai: List[int]) -> int:
    dp = [-1] * (vi[-1] + 1)
    dp[0] = 0

    def updateDp(dp: List[int], i: int, a: int) -> int:
        if i >= a and dp[i - a] >= 0:
            return dp[i - a] + 1
        else:
            return -1

    for i in range(1, len(dp)):
        a = [updateDp(dp, i, a) for a in ai]
        a = list(filter(lambda x: x >= 0, a))
        if len(a) > 0:
            dp[i] = min(a)

    ci = [dp[v] for v in vi]
    if all([a >= 0 for a in ci]):
        return sum(ci)
    else:
        return -1

if __name__ == '__main__':
    main()