#include <bits/stdc++.h>

#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define RFOR(i, a, b) for (ll i = (b)-1; i >= (a); i--)
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define rep1(i, n) for (ll i = 1; i <= (n); i++)
#define rrep(i, n) for (ll i = (n)-1; i >= 0; i--)

#define pb push_back
#define mp make_pair
#define fst first
#define snd second
#define show(x) cout << #x << " = " << x << endl
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
#define pii pair<int, int>
#define vi vector<int>

using namespace std;
template <class S, class T>
ostream& operator<<(ostream& o, const pair<S, T>& p)
{
    return o << "(" << p.first << "," << p.second << ")";
}
template <class T>
ostream& operator<<(ostream& o, const vector<T>& vc)
{
    o << "sz = " << vc.size() << endl
      << "[";
    for (const T& v : vc)
        o << v << ",";
    o << "]";
    return o;
}
using ll = long long;
constexpr ll MOD = 1000000007;
constexpr int INF = numeric_limits<int>::max() / 10;

int v[4];
int make(int a, int b, int c)
{
    int dp[31];
    for (int i = 0; i <= 30; i++) {
        dp[i] = INF;
    }
    dp[0] = 0;
    for (int i = 1; i <= 30; i++) {
        if (i >= a) {
            dp[i] = min(dp[i], dp[i - a] + 1);
        }
        if (i >= b) {
            dp[i] = min(dp[i], dp[i - b] + 1);
        }
        if (i >= c) {
            dp[i] = min(dp[i], dp[i - c] + 1);
        }
    }
    return dp[v[0]] + dp[v[1]] + dp[v[2]] + dp[v[3]];
}

int main()
{
    for (int i = 0; i < 4; i++) {
        cin >> v[i];
    }
    int mini = INF;
    for (int a = 1; a <= 30; a++) {
        for (int b = a; b <= 30; b++) {
            for (int c = b; c <= 30; c++) {
                mini = min(mini, make(a, b, c));
            }
        }
    }
    cout << mini << endl;
    return 0;
}