using System;
 
class Program
{
    static void Main()
    {
        var n = Console.ReadLine();
        var arr = Console.ReadLine().Trim().Split(' ');
        long ans = 1;
 
        long DigitalRoot(long n)
        {
            if (n == 0) return 0;
            long r = n % 9;
            return (r == 0) ? 9 : r;
        }
 
        foreach (var val in arr)
        {
            var x = long.Parse(val);
            ans *= DigitalRoot(x);
        }
 
        ans = DigitalRoot(ans);
        Console.WriteLine(ans);
    }
}