import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        long i,m,n;
        n=in.nextLong();
        m=in.nextLong();
        if(m==1)System.out.println(n-1);
        else if(n==1)System.out.println(m-1);
        else
        {
            System.out.println(n*m-1);
        }
    }
}