#include <bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<(b);++i)
#define erep(i,a,b) for(int i=a;i<=(int)(b);++i)
#define per(i,a,b) for(int i=(a);i>(b);--i)
#define eper(i,a,b) for(int i=(a);i>=b;--i)
#define pb push_back
#define mp make_pair
#define INF 1001001001
#define MOD 1000000007
#define ALL(x) begin(x),end(x)
using namespace std;
typedef long long ll;
typedef pair<int,int> Pii;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a = b; return 1; } return 0; }
int dy[]={0, 0, 1, -1};
int dx[]={1, -1, 0, 0};
int gcd(int a,int b){return b?gcd(b,a%b):a;}
int lcm(int a,int b){return a/gcd(a, b)*b;}

int n, x, a, b;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
    cin >> n >> x >> a >> b;
    int ans = x % a == 0 ? x / a : x / a + 1;
    int cnt = ((int)pow(2, n-1) - x) % b == 0 ? ((int)pow(2, n-1) - x) / b : ((int)pow(2, n-1) - x) / b + 1;
    cout << min(ans, cnt) << endl;
    return 0;
}