#include <bits/stdc++.h>
#define rep(i, n) for (ll i = 0; i < n; ++i)
typedef long long ll;
using namespace std;
const int INF = 1e9;

int main() {
    int yasai, niku, c, d;
    cin >> yasai >> niku >> c >> d;

    int ans = 0;
    int sum = 0;
    while (yasai > 0) {
        yasai--;
        ans++;
        niku -= c;

        sum += c + 1;

        if (niku < 0 || sum > d) {
            ans--;
            break;
        }
    }

    cout << ans << endl;

    return 0;
}