import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	V = getlist()
	ans = INF
	for i in range(1, 31):
		for j in range(1, 31):
			for k in range(1, 31):
				DP = [INF] * 60
				DP[0] = 0
				for x in range(30):
					DP[x + i] = min(DP[x] + 1, DP[x + i])
					DP[x + j] = min(DP[x] + 1, DP[x + j])
					DP[x + k] = min(DP[x] + 1, DP[x + k])
				cost = sum([DP[V[i]] for i in range(4)])
				ans = min(ans, cost)

	print(ans)

if __name__ == '__main__':
	main()