static void Main(string[] args)
{
StreamReader read = new StreamReader("input.txt");
StreamWriter writer = new StreamWriter("output.txt");
int n = int.Parse(read.ReadLine());
HT mm = new HT();
for (int i = 0; i < n; ++i)
{
args = read.ReadLine().Split(' ');
switch (args[0])
{
case "put":
mm.Add(args[1], args[2]);
break;
case "get":
writer.WriteLine(mm.Search(args[1]));
break;
case "prev":
writer.WriteLine(mm.Prev(args[1]));
break;
case "next":
writer.WriteLine(mm.Next(args[1]));
break;
case "delete":
mm.Delete(args[1]);
break;
}
}
read.Close();
writer.Close();
}
