v = list(map(int,input().split()))
ans = float('inf')
for a in range(1,31):
	for b in range(a,31):
		for c in range(b,31):
			dp = [float('inf')] * 31
			dp[0] = 0
			for i in range(30):
				if i + a <= 30:
					dp[i + a] = min(dp[i + a],dp[i] + 1)
				if i + b <= 30:
					dp[i + b] = min(dp[i + b],dp[i] + 1)
				if i + c <= 30:
					dp[i + c] = min(dp[i + c],dp[i] + 1)
			ans = min(ans,sum([dp[v[i]] for i in range(4)]))
print(ans)