#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
#include <string>
#include <numeric>
#include <cstring>
#include <cmath>
#include <set>
#include <queue>
#include <stack>

const int MOD = 1e9 + 7;
const int iINF = 1000000000;
const long long int llINF = 1000000000000000000;
#define rep(i, n) for (int i = 0; i < (n); i++)

using namespace std;
using ll = long long int;
using P = pair<int, int>;
using edge = struct
{
    int to;
    int cost;
};

int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

int main()
{
    vector<int> V(4);
    rep(i, 4) cin >> V[i];
    int ans = iINF;
    for (int A = 1; A < 31; A++)
    {
        for (int B = 1; B < 31; B++)
        {
            for (int C = 1; C < 31; C++)
            {
                vector<int> dp(31, 999);
                dp[0] = 0;
                rep(i, 31 - A)
                {
                    dp[i + A] = min(dp[i + A], dp[i] + 1);
                }

                rep(i, 31 - B)
                {
                    dp[i + B] = min(dp[i + B], dp[i] + 1);
                }

                rep(i, 31 - C)
                {
                    dp[i + C] = min(dp[i + C], dp[i] + 1);
                }
                int sum = 0;
                rep(i, 4) sum += dp[V[i]];
                ans = min(ans, sum);
            }
        }
    }

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