DouKaku?

using System;
using System.Text.RegularExpressions;
class P
{
    static void Main()
    {
        var d = new System.Collections.Generic.Dictionary<String, int>();
        var n = 1;
        for (var s = "" ; (s = Console.ReadLine()) != null ; n++)
            new Regex("\\w+").Replace(s, delegate(Match m)
            {
                var k = m.ToString();
                if (!d.ContainsKey(k)) d[k] = n;
                return k;
            });
        foreach (var k in d)
            Console.Write("{0}: {1}\n", k.Key, k.Value);
    }
}