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) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] str = br.readLine().split(" ");
        
        int n = Integer.parseInt(str[0]);
        int m = Integer.parseInt(str[1]);
        
        long N = Math.max(n, m);
        long M = Math.min(n, m);
        
        System.out.println((N - 1) * M + (M - 1));
    }
}