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 sc = new Scanner(System.in);
        long row = sc.nextLong();
        long column = sc.nextLong();
        long cuts = 0;
        cuts = (Math.max(row - 1, column - 1) * (Math.min(row, column)) + Math.min(row -1, column - 1));
        System.out.println(cuts);
    }
}