#include <iostream>
using namespace std;
int main()
{
    long long i=1,j=1,n,m,flag_break=0,k=0,br_knock=0,flag=1;
    cin>>n>>m;
    do
    {
        if (((i==0&&j==0)||(i==0&&j==n-1)||(i==m-1&&j==0)||(i==m-1&&j==n-1))&&k!=0) {flag_break=1; br_knock++;}
        else
        {
            if (i==0) 
            {
                br_knock++; 
                if (flag==4) flag=2;
                else if (flag==3) flag=1;
            }
            else
                if (j==0) 
                {
                    br_knock++;
                    if (flag==4) flag=3;
                    else if (flag==2) flag=1;
                }
                else
                    if (i==m-1) 
                    {
                        br_knock++;
                        if (flag==1) flag=3;
                        else if (flag==2) flag=4;
                    }
                    else
                        if (j==n-1) 
                        {
                            br_knock++;
                            if (flag==3) flag=4;
                            else if (flag==1) flag=2;
                        }
            switch (flag)
            {
                case 1: i++; j++; break;
                case 2: i++; j--; break;
                case 3: i--; j++; break;
                case 4: i--; j--; break;
            }
        }
        k++;
    }
    while (flag_break==0);
    cout<<br_knock<<endl;
    return 0;
}