#include "bits/stdc++.h"
using namespace std;

typedef long long Int;
#define REP(i,n) for(int (i)=0;(i)<(int)(n);++(i))

int dfs(int n, int B[3], int d, int s) {
	if (n == 0) return d;
	if (n < 0) return 999999;
	int res = 999999;
	if (s <= 0) res = min(res, dfs(n - B[0], B, d + 1, 0));
	if (s <= 1) res = min(res, dfs(n - B[1], B, d + 1, 1));
	if (s <= 2) res = min(res, dfs(n - B[2], B, d + 1, 2));
	return res;
}

int check(int a[4], int B[3]) {
	int res = 0;
	REP(i, 4) res += dfs(a[i], B, 0, 0);
	return res;
}

int a[4];
int main() {
	REP(i, 4) cin >> a[i];
	sort(a, a + 4);
	int best = 999999;
	if (a[0] == a[1] || a[1] == a[2] || a[2] == a[3]) {
		best = 4;
	}
	else
	{
		for (int A = 1; A <= a[0]; A++) {
			for (int B = A + 1; B <= a[3]; B++) {
				for (int C = B + 1; C <= a[3]; C++) {
					int bs[] = { A, B, C };
					int x = check(a, bs);
					if (best > x) best = x;
				}
			}
		}
}
	cout << best << endl;
}