#include #define MAX_N 100001 #define INF_INT 2147483647 #define INF_LL 9223372036854775807 #define REP(i,n) for(int i=0;i<(int)(n);i++) using namespace std; typedef long long int ll; typedef pair P; void init(int n); int find(int n); void unite(int x,int y); bool same(int x, int y); ll bpow(ll,ll,ll); typedef vector vec; typedef vector mat; mat mul(mat &A,mat &B); mat pow(mat A,ll n); int dx[4] = {1,0,0,-1}; int dy[4] = {0,1,-1,0}; vector primes(0); vector prime(400000,true); void erast(){ prime[0] = false; prime[1] = false; for(int i=2;i<400000;i++){ if(prime[i]){ primes.push_back(i); for(int j=i+i;j<400000;j+=i){ prime[j] = false; } } } } bool cmp_P(const P &a,const P &b){ return a.second < b.second; } int main() { ll N,X,A,B,at=0,he=0; cin >> N >> X >> A >> B; at = (X+A-1)/A; he = (((1 << (N-1))-X)+B-1)/B; cout << min(at,he) << endl; return 0; }