#include <bits/stdc++.h>
using namespace std;
#define REP(i,a) for(int i = 0; i < (a); i++)
#define ALL(a) (a).begin(),(a).end()
typedef long long ll;
typedef pair<int, int> P;
const int INF = 1e9;
const int MOD = 1e9 + 7;

signed main(){
    int a,b,c,d;
    cin >> a >> b >> c >> d;
    int ans = 0, cnt = 0;
    for(int i = 1; i <= b; i++){
        cnt++;
        if(cnt > d){
            break;
        }
        if(i % c == 0){
            ans++;
            cnt++;
        }
    }
    cout << min(a, ans) << endl;
}