#include <bits/stdc++.h>
using namespace std;

using ll = long long;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    long n,m,p,q;
    cin >> n >> m >> p >> q;

    long my = (12 + q) * m;
    long yy = n / my;
    long mm{ 0 };
    long nw = yy * my;
    for (int i = 1; i < 12; ++i)
    {
        ++mm;
        if (i >= p && i <= p + q - 1)
            nw += m * 2;
        else
            nw += m;

        if (nw >= n)
            break;
    }

    long res = yy * 12 + mm;
    cout << res << "\n";

    return 0;
}