static void Main()
{
var n = int.Parse(Console.ReadLine());
var r = new List <string>();
var set = new SortedSet <string>();
var d = new MultiMap <string, string>();
for (int i = 0; i < n; i++)
{
var q = Console.ReadLine().Split();
if (q[0] == "0")
{
set.Add(q[1]);
d.Add(q[1], q[2]);
}
else if (q[0] == "1")
{
r.AddRange(d.ReadValues(q[1]));
}
else if (q[0] == "2")
{
d.Remove(q[1]);
set.Remove(q[1]);
}
else
{
r.AddRange(set.GetViewBetween(q[1], q[2]).SelectMany(x => d[x].Select(v => $"{x} {v}")));
}
}
Console.WriteLine(string.Join("\n", r));
}
static void Main()
{
var n = int.Parse(Console.ReadLine());
var qs = new int[n].Select(_ => Console.ReadLine().Split()).ToArray();
var keys = qs.Select(q => q[1]).Concat(qs.Where(q => q[0] == "3").Select(q => q[2])).Distinct().ToArray();
Array.Sort(keys);
var keymap = Enumerable.Range(0, keys.Length).ToDictionary(i => keys[i], i => i);
var r = new List <string>();
var set = new SortedSet <int>();
var d = new MultiMap <int, string>();
foreach (var q in qs)
{
var keyInt = keymap[q[1]];
if (q[0] == "0")
{
set.Add(keyInt);
d.Add(keyInt, q[2]);
}
else if (q[0] == "1")
{
r.AddRange(d.ReadValues(keyInt));
}
else if (q[0] == "2")
{
d.Remove(keyInt);
set.Remove(keyInt);
}
else
{
r.AddRange(set.GetViewBetween(keyInt, keymap[q[2]]).SelectMany(x => d[x].Select(v => $"{keys[x]} {v}")));
}
}
Console.WriteLine(string.Join("\n", r));
}