#include <bits/stdc++.h>
using namespace std;
//#include <atcoder/all>
//using namespace atcoder;
using ll=long long;
using Graph=vector<vector<int>>;
#define MAX 1000000
#define MOD 1000000007
//#define MOD 998244353
#define INF 1000000000
//#define INF 1000000000000000000

int main(){
  vector<int> V(4);
  for(int i=0;i<4;i++){
    cin>>V[i];
  }
  int ans=1000;
  for(int a=1;a<=30;a++){
    for(int b=a+1;b<=30;b++){
      for(int c=b+1;c<=30;c++){
        vector<int> dp(30+1,100000);
        dp[0]=0;
        for(int i=a;i<=30;i++){
          dp[i]=min(dp[i],dp[i-a]+1);
        }
        for(int i=b;i<=30;i++){
          dp[i]=min(dp[i],dp[i-b]+1);
        }
        for(int i=c;i<=30;i++){
          dp[i]=min(dp[i],dp[i-c]+1);
        }
        ans=min(ans,dp[V[0]]+dp[V[1]]+dp[V[2]]+dp[V[3]]);
      }
    }
  }
  cout<<ans<<endl;
}