using System;
using System.Collections.Generic;
using System.IO;
class Solution {
    static void Main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution */
            string[] token = Console.ReadLine().Split(' ');
            int n = Convert.ToInt32(token[0]);
            int m = Convert.ToInt32(token[1]);
            int count = 0;
            if(m<n)
            {
                count = n - 1;
                if (m > 1)
                {
                    m = m + 1;
                    for (int i = 1; i < n + 1; i++)
                    {
                        while (m != 0)
                        {
                            m = m - 1;
                            count++;
                        }
                    }
                }
            }
            else
            {
                count = m - 1;
                if (n > 1)
                {
                    n = n + 1;
                    for (int i = 1; i < m + 1; i++)
                    {
                        while (n != 0)
                        {
                            n = n - 1;
                            count++;
                        }
                    }
                }
            }
            Console.WriteLine(count);
    }
}