#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <cstring>

typedef long long ll;
using namespace std;

#define mod 1000003
#define INF 10000000
#define LLINF 2000000000000000000LL

#define SIZE 10000

int main(){
    int v[4],ans=INF;
    int dp[70],l[3];
    
    for(int i=0;i<4;i++)
        scanf("%d",&v[i]);
    
    for(int a=1;a<=30;a++){
        for(int b=a+1;b<=30;b++){
            for(int c=b+1;c<=30;c++){
                
                l[0]=a;
                l[1]=b;
                l[2]=c;
                
                for(int i=1;i<=60;i++){
                    dp[i]=INF;
                }
                
                dp[0]=0;
                
                for(int i=0;i<3;i++){
                    for(int j=0;j<=30;j++){
                        if(dp[j]!=INF){
                            dp[j+l[i]]=min(dp[j+l[i]],dp[j]+1);
                        }
                    }
                }
                
                int sum=0;
                
                for(int i=0;i<4;i++){
                    sum+=dp[v[i]];
                }
                
                ans = min(ans,sum);
            }
        }
    }
    
    printf("%d\n",ans);
    
    return 0;
}