#include <bits/stdc++.h>
#define INF 2147483647
#define INF_LL 9223372036854775807
#define MOD 1000000007
using namespace std;
typedef long long int ll;
typedef unsigned long long int ull;


int main() {
	int A, B, C, D;
	cin >> A >> B >> C >> D;
	int ans = 0;
	while (1) {
		if (A == 0 || B == 0 || D == 0)break;
		if (B >= C) {
			B -= C; A--;
			ans++;
			D -= C + 1;
			continue;
		}
		break;
	}
	cout << ans << endl;
}