import java.io.*;
import java.util.*;
import java.math.BigInteger;

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 sc=new Scanner(System.in);
        int n=sc.nextInt();
        int  m=sc.nextInt();
        BigInteger b1=new BigInteger(Integer.toString(n));
         BigInteger b2=new BigInteger(Integer.toString(m));
        b2=b1.multiply(b2);
        BigInteger b3=BigInteger.valueOf(1);
        b2=b2.subtract(b3);
        System.out.print(b2);
        
        
        
    }
}