#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <math.h>

using ll = long long;
using namespace std;

const int MOD = 1e9+7;

int main() {
    int N, X, A, B, cnt1, cnt2;
    cnt1 = cnt2 = 0;
    cin >> N >> X >> A >> B;
    int x = X;
    while (!(x & (1<<(N-1)) || x == 0)) {
        x -= A;
        cnt1++;
    }
    x = X;
    while (!(x & (1<<(N-1)) || x == 0)) {
        x += B;
        cnt2++;
    }
    cout << min(cnt1, cnt2) << endl;
    return 0;
}