#include <algorithm>
#include <array>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <numeric>
#include <optional>
#include <queue>
#include <set>
#include <sstream>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

int main() {
    int32_t n, m, p, q;
    cin >> n >> m >> p >> q;
    int32_t ans = n / ((12 - q) * m + q * (2 * m)) * 12;
    n %= ((12 - q) * m + q * (2 * m));
    for (auto i = 1; i < p && n > 0; ++i) {
        ++ans;
        n -= m;
    }
    for (auto i = p; i < p + q && n > 0; ++i) {
        ++ans;
        n -= m * 2;
    }
    ans += (n + m - 1) / m;
    cout << ans << endl;
    return 0;
}