#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi  = vector<int>; using vb  = vector<bool>; using vd  = vector<double>; using vl  = vector<ll>;
using vvi = vector<vi>;  using vvb = vector<vb>;   using vvd = vector<vd>;     using vvl = vector<vl>;

#define REP(i,n) for(ll i=0; i<(n); ++i)
#define FOR(i,b,n) for(ll i=(b); i<(n); ++i)

int main() {
	ll v0, v1, v2, v3;
	cin >> v0 >> v1 >> v2 >> v3;

	ll ans = 150;
	FOR(a, 1, 31) FOR(b, 1, 31) FOR(c, 1, 31) {
		vi dp(31, 150); dp[0] = 0;
		REP(i, dp.size()) {
			if (i + a < dp.size()) dp[i + a] = min(dp[i + a], dp[i] + 1);
			if (i + b < dp.size()) dp[i + b] = min(dp[i + b], dp[i] + 1);
			if (i + c < dp.size()) dp[i + c] = min(dp[i + c], dp[i] + 1);
		}
		ans = min<ll>(ans, dp[v0] + dp[v1] + dp[v2] + dp[v3]);
	}

	cout << ans << endl;

	return 0;
}