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,m;
        n= in.nextInt();
        m= in.nextInt();
        BigInteger a=new BigInteger(String.valueOf(n));
        BigInteger b=new BigInteger(String.valueOf(m));
        a=a.multiply(b);
        a=a.subtract(new BigInteger("1"));
        System.out.println(a);
    }
}