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 scan = new Scanner(System.in);
        long n = scan.nextInt();
        long m = scan.nextInt();

        System.out.println(Math.max(n - 1 + (m - 1) * n, (n - 1) * m + m - 1));

    }

}