#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

long long int recur(long long int n,long long int m)
{
  if(n==1 && m==1 || (m==0 || n==0)) return (0);
  else if(n==1) return (m-1);
  else if(m==1) return (n-1);
  else if(m==2 && n==2) return 2;
  else if(m==3 && n==3) return 8;
  else if((m==2 && n==3) || (m==3 && n==2)) return 5;
  else{
      if(n>=m){
          if(n%2==0)
            return (1+2*recur(n/2,m));  
          else
              return (2+2*recur(n/2,m)+recur(n%2,m));
      }   
      else{
          if(m%2==0)
            return (1+2*recur(m/2,n));  
          else
              return (2+2*recur(m/2,n)+recur(m%2,n));
      }    
  }
}


int main() {
    long long int n,m,cuts;
    cin>>n>>m;
    cout<<recur(n,m);
    
    return 0;
}