#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <sstream>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <numeric>
#include <cctype>
#include <tuple>
#include <climits>
#include <bitset>
#include <cassert>
#include <random>

#ifdef _MSC_VER
#include <agents.h>
#endif

#define FOR(i, a, b) for(int i = (a); i < (int)(b); ++i)
#define rep(i, n) FOR(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define REV(v) v.rbegin(), v.rend()
#define MEMSET(v, s) memset(v, s, sizeof(v))
#define UNIQUE(v) (v).erase(unique(ALL(v)), (v).end())
#define MP make_pair
#define MT make_tuple

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

template<class T> inline void chmax(T& a, const T& b) { if (b > a) a = b; }
template<class T> inline void chmin(T& a, const T& b) { if (b < a) a = b; }

const double EPS = 1e-9;

int a[3];
int v[4];

int calc(){
	vector<int> dp(31, 1e8);
	dp[0] = 0;
	for (int i = 0; i < 3; ++i){
		for (int j = 0; j + a[i] <= 30; ++j){
			dp[j + a[i]] = min(dp[j + a[i]], dp[j] + 1);
		}
	}

	int res = 0;
	rep(i, 4) res += dp[v[i]];
	return res;
}

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);

	rep(i, 4) cin >> v[i];

	int ans = 1e8;
	FOR(i, 1, 31){
		a[0] = i;
		FOR(j, i + 1, 31){
			a[1] = j;
			FOR(k, j + 1, 31){
				a[2] = k;
				ans = min(ans, calc());
			}
		}
	}

	cout << ans << endl;



	return 0;
}