import sys

sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


x,y,z,w = MI()
inf = 10**18
ans = inf
for i in range(1,31):
    for j in range(1,31):
        for k in range(1,31):
            dp = [inf]*31
            dp[0] = 0
            for l in range(1,31):
                if l >= i:
                    dp[l] = min(dp[l],dp[l-i]+1)
                if l >= j:
                    dp[l] = min(dp[l],dp[l-j]+1)
                if l >= k:
                    dp[l] = min(dp[l],dp[l-k]+1)
            ans = min(ans,dp[x]+dp[y]+dp[z]+dp[w])

print(ans)