import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int[] arr = new int[4];
		for (int i = 0; i < 4; i++) {
		    arr[i] = sc.nextInt();
		}
		int min = Integer.MAX_VALUE;
		for (int i = 1; i <= 30 - 2; i++) {
		    for (int j = i + 1; j <= 30 - 1; j++) {
		        for (int k = j + 1; k <= 30; k++) {
		            int[] dp = getDp(i, j, k);
		            int count = 0;
		            for (int l = 0; l < 4; l++) {
		                count += dp[arr[l]];
		            }
		            min = Math.min(min, count);
		        }
		    }
		}
		System.out.println(min);
   }
   static int[] getDp(int a, int b, int c) {
       int[] dp = new int[31];
       Arrays.fill(dp, Integer.MAX_VALUE / 100);
       dp[0] = 0;
       for (int i = 0; i < 31; i++) {
           int idx = 1;
           while (i + idx * a < 31) {
               dp[i + idx * a] = Math.min(dp[i + idx * a], dp[i] + idx);
               idx++;
           }
           idx = 1;
           while (i + idx * b < 31) {
               dp[i + idx * b] = Math.min(dp[i + idx * b], dp[i] + idx);
               idx++;
           }
           idx = 1;
           while (i + idx * c < 31) {
               dp[i + idx * c] = Math.min(dp[i + idx * c], dp[i] + idx);
               idx++;
           }
       }
       return dp;
   }
}