#include <bits/stdc++.h>

using namespace std;

namespace {

    typedef double real;
    typedef long long ll;

    template<class T> ostream& operator<<(ostream& os, const vector<T>& vs) {
        if (vs.empty()) return os << "[]";
        auto i = vs.begin();
        os << "[" << *i;
        for (++i; i != vs.end(); ++i) os << " " << *i;
        return os << "]";
    }
    template<class T> istream& operator>>(istream& is, vector<T>& vs) {
        for (auto it = vs.begin(); it != vs.end(); it++) is >> *it;
        return is;
    }

    const int INF = 1<<28;
    vector<int> xs;
    void input() {
        xs.resize(4); cin >> xs;
    }

    int cache[31][31][31][31];
    int f(int v, int a, int b, int c) {
        if (v < 0) return INF;
        if (v == 0) return 0;
        int& x = cache[v][a][b][c];
        if (x >= 0) return x;
        return x = min(f(v - c, a, b, c) + 1, min(f(v - a, a, b, c) + 1, f(v - b, a, b, c) + 1));
    }

    int calc(int a, int b, int c) {
        int ans = 0;
        for (int i = 0; i < 4; i++) {
            ans += f(xs[i], a, b, c);
        }
        return ans;
    }

    void solve() {
        int ans = INF;
        sort(xs.begin(), xs.end());
        memset(cache, -1, sizeof(cache));
        for (int a = 1; a <= 30; a++) {
            for (int b = a + 1; b <= 30; b++) {
                for (int c = b + 1; c <= 30; c++) {
                    ans = min(ans, calc(a, b, c));
                }
            }
        }
        cout << ans << endl;
    }
}

int main() {
    input(); solve();
    return 0;
}