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

int main()
{
	int A, B, C, D;
	cin >> A >> B >> C >> D;

	int ans;
	for( ans = A; ans >= 0; ans-- ) {
		int b = ans * C;
		int d = ans + b;
		if( b <= B && d <= D ) break;
	}

	cout << ans << endl;
}