import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        long n=sc.nextLong();
        long m=sc.nextLong();
        long cut=0;
        
            if((m>1)&&(n>1))
                cut=(n*m)-1;
            else if (m==1)
                cut=n-1;
            else if(n==1)
                cut=m-1;
            
           /* else
                {
                cut=m+n;;
            }*/
        System.out.println(cut);
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
    }
}