#ifndef _GLIBCXX_NO_ASSERT
#include <cassert>
#endif
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#if __cplusplus >= 201103L
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
#endif
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#if __cplusplus >= 201103L
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#endif

using namespace std;
using i64 = int64_t;
using vi = vector<i64>;
using vvi = vector<vi>;
constexpr i64 MOD = 1000000000;


int main() {
    vi vs(4);
    for (int i = 0; i < 4; i++) {
        cin >> vs[i];
    }
    int ans = 1e9;
    for (int a = 1; a <= 30; a++) {
        for (int b = 1; b <= 30; b++) {
            for (int c = 1; c <= 30; c++) {
                int cnt = 0;
                const int INF = 1e9;
                vi kek(31, INF);
                kek[0] = 0;
                for (int i = 0; i < 31; i++) {
                    if (kek[i] != INF && i + a < 31) {
                        kek[i + a] = min(kek[i + a], kek[i] + 1);
                    }
                }
                for (int i = 0; i < 31; i++) {
                    if (kek[i] != INF && i + b < 31) {
                        kek[i + b] = min(kek[i + b], kek[i] + 1);
                    }
                }
                for (int i = 0; i < 31; i++) {
                    if (kek[i] != INF && i + c < 31) {
                        kek[i + c] = min(kek[i + c], kek[i] + 1);
                    }
                }
                for (int i = 0; i < 4; i++) {
                    if (kek[vs[i]] == INF) {
                        cnt = 1e9;
                        break;
                    } else {
                        cnt += kek[vs[i]];
                    }
                }
                ans = min(ans, cnt);
            }
        }
    }
    cout << ans << endl;
}