#include<iostream>
#include<algorithm>
using namespace std;
int main(void){
	int v[4], res = 1000;
	for (int i = 0; i < 4; i++){
		cin >> v[i];
	}
	for (int a = 1; a < 31; a++)for (int b = 1; b < 31; b++)for (int c = 1; c < 31; c++){
		int dp[31] = { 0 };
		for (int i = 1; i < 31; i++){
			dp[i] = 1000;
		}
		for (int i = a; i < 31; i++)dp[i] = min(dp[i], dp[i - a] + 1);
		for (int i = b; i < 31; i++)dp[i] = min(dp[i], dp[i - b] + 1);
		for (int i = c; i < 31; i++)dp[i] = min(dp[i], dp[i - c] + 1);

		int sum = 0;
		for (int i = 0; i < 4; i++){
			sum += dp[v[i]];
		}
		res = min(res, sum);
	}
	cout << res << endl;
	return 0;
}