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) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        Scanner scan = new Scanner(System.in);
        BigInteger n = new BigInteger(scan.nextInt()+"");
        BigInteger m = new BigInteger(scan.nextInt()+"");
        BigInteger t = new BigInteger("0");
        BigInteger t1 = new BigInteger("-1");
        t=t.add(m.add(t1));
        t=t.add(m.multiply(n.add(t1)));
        System.out.print(t);
    }
}