#include <bits/stdc++.h>

#define REP(i, x, n) for(int i = x; i < (int)(n); i++)
#define rep(i, n) REP(i, 0, n)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define F first
#define S second
#define mp make_pair

using namespace std;

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

int main() {
  // ios_base::sync_with_stdio(false);
  int v0, v1, v2, v3;
  cin >> v0 >> v1 >> v2 >> v3;

  int ans = 10000;
  REP(A, 1, 31) REP(B, A + 1, 31) REP(C, B + 1, 31) {
    vector<int> v{A, B, C};
    vector<int> dp(31, 10000);
    dp[0] = 0;
    rep(i, 3) rep(j, 31) if(dp[j] != 10000 && j + v[i] < 31) {
      dp[j + v[i]] = min(dp[j + v[i]], dp[j] + 1);
    }
    ans = min(ans, dp[v0] + dp[v1] + dp[v2] + dp[v3]);
  }

  cout << ans << endl;
  
  return 0;
}