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 in = new Scanner(System.in);
        int n = in.nextInt();
        int m = in.nextInt();
        if(n==1){
            System.out.println(m-1);
        }
         else if(m==1){
            System.out.println(n-1);
        }
        else{
            System.out.println((long)n*m-1);
        }
    }
}