#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define ALL(v) v.begin(),v.end()
typedef long long ll;

#include<bits/stdc++.h>
using namespace std;

int main(){
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);

  ll n,m;
  cin>>n>>m;
  
  auto f=[&](ll x){
    ll now=x;
    rep(i,n-1){
      if(now==1) break;
      now=(now+1)/2;
    }
    if(now==1) return true;
    return false;
  };
  
  ll ok=1,ng=m+2;
  while(ng-ok>1){
    ll mid=(ok+ng)/2;
    if(f(mid)) ok=mid;
    else ng=mid;
  }
  ll t=min(ok,m);
  ll ans=t;
  ll now=t;
  rep(i,n-1){
    now=(now+1)/2;
    ans+=now;
  }
  cout<<ans<<endl;
  
  return 0;
}