C# Solution

    Dictionary<string,uint> phoneList = new Dictionary<string,uint>();

    int entries = int.Parse(Console.ReadLine());

    while(entries > 0)
    {
        string[] entry = Console.ReadLine().Split();
        string name = entry[0];
        uint tel = uint.Parse(entry[1]);

        phoneList.Add(name, tel);

        entries--;
    }

    bool lookUp = true;

    while(lookUp)
    {
        string lookFor = Console.ReadLine();

        if(lookFor == string.Empty || lookFor == null)
        {
            lookUp = false;
        }            
        else
        {
            if(phoneList.ContainsKey(lookFor))
            {
                Console.WriteLine("{0}={1}", lookFor, phoneList[lookFor]);
            }
            else Console.WriteLine("Not found");
        }
    }