using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


class Solution
{
    public static void Main(String[] args)
    {
        UInt64 n, m;

        UInt64[] ints = Array.ConvertAll(Console.ReadLine().Split(' '), Convert.ToUInt64);
        n = ints[0];
        m = ints[1];

        Console.WriteLine(MakeCuts(n, m));
    }

    private static UInt64 MakeCuts(UInt64 n, UInt64 m)
    {
        return n * m - 1;
    }
}