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();
        
        System.out.println(count(n, m));
    }
    
    public static long count(int n, int m) {
        if (n == 1 && m == 1) return 0;
        if (n == 1) return (m - 1);
        if (m == 1) return (n - 1);
        
        return ((n - 1) + (long) n * (m - 1));
    }
}