import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int[] ita = new int[4];
        for (int i = 0; i < 4; i++) {
            ita[i] = sc.nextInt();
        }
        int ans = Integer.MAX_VALUE;
        for (int i = 1; i <= 30; i++) {
            for (int j = i + 1; j <= 30; j++) {
                for (int k = j + 1; k <= 30; k++) {
                    int sum = 0;
                    int[] dp = new int[31];
                    int[] piece = new int[]{i, j, k};
                    for (int l = 0; l < 4; l++) {
                        sum += dfw(ita[l], piece, dp);
                    }
                    ans = Math.min(ans, sum);
                }
            }
        }
        System.out.println(ans);
    }
    
    static int dfw(int size, int[] piece, int[] dp) {
        if (size < 0) {
            return 40;
        }
        if (size == 0) {
            return 0;
        }
        if (dp[size] == 0) {
            dp[size] = Integer.MAX_VALUE;
            for (int x : piece) {
                dp[size] = Math.min(dp[size], dfw(size - x, piece, dp) + 1);
            }
        }
        return dp[size];
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String nextLine() throws Exception {
        return br.readLine();
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}