#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(), (x).end()
using ll = long long;
const ll MOD = 998244353;
#include<atcoder/all>
using namespace atcoder;
using mint = modint998244353;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  ll n,m;cin>>n>>m;
  if(n%2==0){
    cout<<n*m<<endl;
    return 0;
  }
  ll cnt=0;
  while((1<<(cnt+1))<=m){
    cnt++;
  }
  cout<<m*(n-2)+((1<<cnt)-1)+(m^((1<<cnt)-1));
}