#include "bits/stdc++.h"
using namespace std;
#define fastcin {\
    cin.tie(0);\
    ios::sync_with_stdio(false);\
}
#define rep(i, a, b) for(int i = a; i < b; i++)
#define rrep(i, a, b) for(int i = a; i >= b; i--)
#define fore(i, a) for(auto &i:a)
#define print(x) cout << x << "\n"
#define SORT(a, n) sort(a, a+n);
#define REVERSE(a,n) reverse(a,a+n);
#define VSORT(v) sort(v.begin(), v.end());
#define VREVERSE(v) reverse(v.begin(), v.end());
#define MOD 1000000007
#define yes "YES"
#define no "NO"
typedef long long ll;

int main() {
    fastcin;
    int N, X, A, B;
    cin >> N >> X >> A >> B;
    double att = (double)X/A;
    double heal = (double)(pow(2, N-1)-X)/B;
    double ans = min(att, heal);
    if(ans!=0) {
        ans++;
        ans = (int)ans;
    }
    print(ans);
    return 0;
}