#include <iostream>
using namespace std;

const int MAX = 30;

int board[3];
int dp[100];
int V[5];

int solve(){
    for(int i=0;i<=MAX;i++)dp[i] = 100;

    dp[0] = 0;
    for(int i=0;i<MAX;i++){
        for(int j=0;j<4;j++){
            dp[i + board[j]] = min(dp[i + board[j]], dp[i] + 1);
        }
    }
    
    int res = 0;
    for(int i=0;i<4;i++)res += dp[V[i]];
    
    return res;
}

int main(){
    for(int i=0;i<4;i++)cin >> V[i];
    
    int res = 100;
    for(int A=1;A<=MAX;A++)for(int B=A+1;B<=MAX;B++)for(int C=B+1;C<=MAX;C++){
        board[0] = A;
        board[1] = B;
        board[2] = C;
        
        res = min(res, solve());
    }
    
    cout << res << endl;
    return 0;
}