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) throws IOException {
            //BufferedReader bf = new BufferedReader ( new InputStreamReader (System.in));
            Scanner scan = new Scanner (System.in);
            //int in = Integer.parseInt(bf.readLine());
            long im = scan.nextLong();
            long in = scan.nextLong();
            //int im = Integer.parseInt(bf.readLine());
            System.out.println((im*in)-1);
    }
}