using System;

​

public class Program

{

    public static void Main()

    {

        int m = Convert.ToInt32(Console.ReadLine());

        int x = m;

        int y = m;

        int z = m % 10;

        while (y > 0)

        {

            x = y % 10;

            y = y / 10;

        }

​

        int p = x;

        Console.WriteLine(p * z);

    }

}