import sys

input = sys.stdin.readline


def main():
    x, y, z, w = map(int, input().split())
    M = max(x, y, z, w)
    ans = float('inf')
    for a in range(1, M+1):
        for b in range(1, a):
            for c in range(1, b):
                D = [0] + [float('inf')]*M
                for i in range(M):
                    for j in [a, b, c]:
                        if i+j <= M:
                            D[i+j] = min(D[i+j], D[i]+1)
                ans = min(ans, D[x]+D[y]+D[z]+D[w])
    print(ans)


if __name__ == '__main__':
    main()