#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<complex>
#include<bitset>
#include<stack>
#include<unordered_map>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll mod = (ll)(1e+9) + 7;
const ll INF = (ll)1000000007 * 1000000007;
typedef pair<int, int> P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
typedef long double ld;
typedef complex<ld> Point;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
typedef pair<ll, ll> LP;
typedef pair<ld, ld> LDP;
int main() {
	int v[4];
	rep(i, 4)cin >> v[i];
	int out = 10000;
	rep(i, 31) {
		Rep(j, i+1, 31) {
			Rep(k, j + 1, 31) {
				int dp[31];
				fill(dp, dp + 31, 1000);
				dp[0] = 0;
				rep(l, 31) {
					if (l + i < 31) {
						dp[l + i] = min(dp[l + i], dp[l] + 1);
					}
				}
				rep(l, 31) {
					if (l + j < 31) {
						dp[l + j] = min(dp[l + j], dp[l] + 1);
					}
				}
				rep(l, 31) {
					if (l + k < 31) {
						dp[l + k] = min(dp[l + k], dp[l] + 1);
					}
				}
				int s = 0;
				rep(l, 4) {
					s += dp[v[l]];
				}
				out = min(out, s);
			}
		}
	}
	cout << out << endl;
	return 0;
}