#include <iostream>
using namespace std;

const int kINF = 1 << 28;
const int kMAX_LEN = 32;

int v0, v1, v2, v3;
int length[3], dp[kMAX_LEN];

int Knapsack() {
    fill(dp, dp + kMAX_LEN, kINF);
    dp[0] = 0;
    for (int i = 0; i < 3; i++) {
        for (int len = 0; len < kMAX_LEN; len++) {
            if (len - length[i] >= 0) {
                dp[len] = min(dp[len], dp[len - length[i]] + 1);
            }
        }
    }
    return dp[v0] + dp[v1] + dp[v2] + dp[v3];
}

void Solve() {
    int answer = kMAX_LEN;
    for (int a = 1; a <= kMAX_LEN; a++) {
        for (int b = a + 1; b <= kMAX_LEN; b++) {
            for (int c = b + 1; c <= kMAX_LEN; c++) {
                length[0] = a;
                length[1] = b;
                length[2] = c;

                // ここで個数制限なしナップザック
                answer = min(answer, Knapsack());
            }
        }
    }
    cout << answer << endl;
}

int main() {
    cin >> v0 >> v1 >> v2 >> v3;

    Solve();

    return 0;
}