import java.io.*;
import java.util.*;

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 in = new Scanner(System.in);
        long n = in.nextLong();
        long m = in.nextLong();
        long ans = 0;
        if(m > 1 && n > 1){
            ans = (n - 1)*(m) + m - 1;
        }else if(m == 1 && n > 1){
            ans = n - 1;
        }else if(n == 1 && m > 1){
            ans = m - 1;
        }else{
            ans = 0;
        }
        //long 
        System.out.println(ans);
    }
}