/*
TASK:rtri
LANG:C++
*/
#include<iostream>
using namespace std;
int m,n,br,M[30][30],i,j;
int main()
{
cin>>m>>n;
for(i=0;i<n;i++)
 for(j=0;j<m;j++)
  {if(M[i][j]==0)
   {
    br=br+4;
    if(M[i+1][j]==0){br=br+6; M[i+1][j]=2;} 
    M[i][j]=1;   
   }
   if(M[i][j]==2)br=br+4;
}
cout<<br<<endl;
return 0;
}
