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) 
    {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
            Scanner sc=new Scanner(System.in);
            int a=sc.nextInt();
            int b=sc.nextInt();
            int tempA=a;
            int tempB=b;
            int count=0;
            int max=1;
              
            /*   if(a!=1&& b!=1)
                   max=a;
                while(tempA!=1 || tempB!=1)
                {
                  count++;
                    if(tempA!=1)
                    tempA--;
                    else if(tempB!=1)
                    tempB--;
                }*/
               
            
        
            System.out.println(a*b-1);
    }
}