import bisect
import copy
import decimal
import fractions
import heapq
import itertools
import math
import random
import sys
from collections import Counter, deque,defaultdict
from functools import lru_cache,reduce
from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max
def _heappush_max(heap,item):
    heap.append(item)
    heapq._siftdown_max(heap, 0, len(heap)-1)
def _heappushpop_max(heap, item):
    if heap and item < heap[0]:
        item, heap[0] = heap[0], item
        heapq._siftup_max(heap, 0)
    return item
from math import gcd as GCD
read=sys.stdin.read
readline=sys.stdin.readline
readlines=sys.stdin.readlines

V0,V1,V2,V3=map(int,readline().split())
inf=1<<60
ans=inf
for C in range(1,31):
    for B in range(1,C):
        for A in range(1,B):
            cnt=[inf]*31
            cnt[0]=0
            for i in range(1,31):
                if i>=A:
                    cnt[i]=min(cnt[i],cnt[i-A]+1)
                if i>=B:
                    cnt[i]=min(cnt[i],cnt[i-B]+1)
                if i>=C:
                    cnt[i]=min(cnt[i],cnt[i-C]+1)
            ans=min(ans,cnt[V0]+cnt[V1]+cnt[V2]+cnt[V3])
print(ans)