using System;
using System.Collections.Generic;
 
class Program
{
    static void Main()
    {
        string line;
 
        while (!string.IsNullOrEmpty(line = Console.ReadLine()))
        {
            if (HasCharTwice(line))
            {
                Console.WriteLine(line);
            }
        }
    }
 
    static bool HasCharTwice(string line)
    {
        Dictionary<char, int> charCount = new Dictionary<char, int>();
 
        foreach (char c in line)
        {
            if (char.IsWhiteSpace(c))
            {
                continue;
            }
 
            if (charCount.ContainsKey(c))
            {
                charCount[c]++;
            }
            else
            {
                charCount[c] = 1;
            }
        }
 
        foreach (int count in charCount.Values)
        {
            if (count == 2)
            {
                return true;
            }
        }
 
        return false;
    }
}

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