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);
        int n = sc.nextInt();
        int m = sc.nextInt();
        long result = 0;
        
        if (1 == m || 1 == n)
        {
            if (1 == m)
            {
                result = n-1;
            }
            else
            {
                result = m-1;
            }
        }
        else
        {
            result = (m-1) + (m * (n-1));
        }
        
        
        System.out.println(result);
    }
}