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 s=new Scanner(System.in); long n=s.nextInt(); long m=s.nextInt(); long res=n*m-1; System.out.println(res); /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */ } }