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

public class Hello
{
    public static void Main()
    {
        var sb = new StringBuilder();
        var n = int.Parse(Console.ReadLine().Trim());
        for (int i = 0; i < n; i++)
            sb.Append(getAns(Console.ReadLine().Trim()));
        Console.Write(sb);
    }
    public static string getAns(string s)
    {
        var sL = s.Length;
        var a = new List<int>();
        var b = new List<int>();
        for (int i = 0; i < sL; i++) a.Add(int.Parse(s[i].ToString()));
        while (a.Count() > 1)
        {
            b.Clear();
            for (int j = 0; j < a.Count() - 1; j++)
            {
                var w = a[j] + a[j + 1];
                if (w >= 10) w -= 9;
                b.Add(w);
            }
            a.Clear();
            foreach (var x in b) a.Add(x);
        }
        return string.Format("{0}\n", a[0]);
    }
}