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

int main()
{
    int N, M, P, Q;
    cin >> N >> M >> P >> Q;
    int year = Q * 2 * M + (12 - Q) * M;
    long long ans = 0;
    ans = (N / year) * 12;
    N %= year;

    for (int i = 1; i <= 12; i++)
    {
        if (P <= i && i < P + Q)
        {
            N -= 2 * M;
        }
        else
        {
            N -= M;
        }
        ans++;
        if (N <= 0)
        {
            break;
        }
    }
    cout << ans;
}