#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, tmpX, tmpB;
    int ansA = 0, ansB = 0;
    cin >> N >> X >> A >> B;
    tmpX = X;
    tmpB = B;
    rep(i, 0, 32-N) {
        tmpX = tmpX << 1;
        tmpB = tmpB << 1;
    }
    while(tmpX > 0) {
        tmpX += tmpB;
        ansB++;
    }

    int mod = X%A;
    ansA = X/A;
    if(mod) ansA++;
    print(min(ansA, ansB));
    return 0;
}