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 sc=new Scanner(System.in);
        long  n=sc.nextInt();
        long  m=sc.nextInt();
        
        long  maxNum=0;
        long  minNum=0;
        if(n>m){
            maxNum=n;
            minNum=m;
        }
        else{
            maxNum=m;
            minNum=n;
        }
        long result1=(minNum-1)+((maxNum-1)*(minNum));
        long result2=(maxNum-1)+((minNum-1)*(maxNum));
        System.out.println(Math.min(result1,result2));
    }
}