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();
         if (n==1 || m==1){
        System.out.println(Math.max(n,m)-1);
    }else{
        long ans1 = n-1 + n*(m-1);
        long ans2 = m-1 + m*(n-1);
        System.out.println(Math.min(ans1,ans2));
    }
    }
}