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 = in.nextInt();
        int m = in.nextInt();
        int min=Math.min(n,m);
        m=m+n-min;
        long ans=(long)m*min-1;
        System.out.println(ans);
    }
}