#include<bits/stdc++.h>
using namespace std;
map<pair<long,long>,long>mp;
long getAns(long m, long n)
{
    long max1=max(m,n),min1=min(m,n);
    pair<long,long> p1;
    p1.first=max1;
    p1.second=min1;
    if(mp[p1]!=0)
        return mp[p1];
    if(min1==1)
        {
            mp[p1]=max1-1;
            return max1-1;    
        }
        
    if(max1%2==0)
        {
             mp[p1]=1+2*getAns(max1/2,min1);
               return mp[p1];
        }
        mp[p1]=1+getAns(max1/2,min1)+getAns(max1-max1/2,min1);
       return mp[p1];
}

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    long N,M;
    cin>>N>>M;
    cout<<getAns(N,M)<<endl;
    return 0;
}