using System;
using System.Linq;
using System.Collections.Generic;
using System.IO;

class MyClass
{
    public static void Solve()
    {
        var N = int.Parse(Console.ReadLine());
        var P = Console.ReadLine().Split().ToArray();
        var Q = P.Select(x => x.ToCharArray().Select(y => int.Parse(y.ToString())).Sum());
        var prod = 1;
        foreach (var item in Q)
        {
            prod *= item;
        }
        Console.WriteLine(prod.ToString().ToCharArray().Select(y => int.Parse(y.ToString())).Sum());
    }

    public static void Main()
    {
        var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        Console.SetOut(sw);
        Solve();
        Console.Out.Flush();
    }
}