#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main() {

    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    long int n,m;
    scanf("%ld %ld",&n,&m);
    long int x=0;
    if(n==1&&(m!=1))
        x=m-1;
    else{
        if(m==1&&(n!=1))
            x=n-1;
        else{
        if(n==m)
            x=2*n+1;
        else
            {
            if(n!=1&&m!=1)
                x=n*m-1;
            }
        }
    }
    printf("%ld\n",x);
    return 0;
}