#include "bits/stdc++.h"
using namespace std;
#define print(x) cout<<x<<endl;
#define rep(i,a,b) for(int i=a;i<b;i++)
#define REP(i,a) for(int i=0;i<a;i++)
#define printall(n,array) {for(int i=0;i<n;i++){cout<<array[i]<<" ";}cout<<endl;}
#define U() cout<<endl;
typedef long long ll;
typedef pair<int, int> PI;
typedef pair<int, PI> V;
typedef vector<int> VE;
const ll mod = 1000000007; //10^9+7

int v[4];

int main(){
  REP(i,4)cin>>v[i];
  int ans=mod;
  rep(a,1,32)rep(b,a+1,32)rep(c,b+1,32){
    VE dp(32,999);
    dp[0]=0;
    REP(i,32-a){
      dp[i+a]=min(dp[i+a],dp[i]+1);
    }
    REP(i,32-b){
      dp[i+b]=min(dp[i+b],dp[i]+1);
    }
    REP(i,32-c){
      dp[i+c]=min(dp[i+c],dp[i]+1);
    }    
    ans=min(ans,dp[v[0]]+dp[v[1]]+dp[v[2]]+dp[v[3]]);
  }
  print(ans);
}