Problem:
Multi-Set

For a set $S$ of integers, perform a sequence of the following operations. Note that multiple elements can have equivalent values in $S$.

insert($x$): Insert $x$ to $S$ and report the number of elements in $S$ after the operation.

find($x$): Report the number of $x$ in $S$.

delete($x$): Delete all $x$ from $S$.

dump($L$, $R$): Print elements $x$ in $S$ such that $L \leq x \leq R$.

Input

The input is given in the following format.

$q$
$query_1$
$query_2$
:
$query_q$

Each query $query_i$ is given by

0 $x$

or

1 $x$

or

2 $x$

or

3 $L$ $R$

where the first digits 0, 1, 2 and 3 represent insert, find, delete and dump operations respectively.

Output

For each insert operation, print the number of elements in $S$.

For each find operation, print the number of specified elements in $S$.

For each dump operation, print the corresponding elements in ascending order. Print an element in a line.

Constraints

$1 \leq q \leq 200,000$

$0 \leq x \leq 1,000,000,000$

The total number of elements printed by dump operations does not exceed $1,000,000$

The sum of numbers printed by find operations does not exceed $2,000,000$

Sample Input 1

10
0 1
0 1
0 2
0 3
2 2
1 1
1 2
1 3
0 4
3 1 4

Sample Output 1

1
2
3
4
2
0
1
4
1
1
3
4

Solution in JAVA (judge verdict: Accepted)

import java.util.Map;
import java.util.Scanner;
import java.util.TreeMap;

public class Main  {
	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int n = scan.nextInt();
		int count = 0;
		TreeMap<Integer, Integer> map = new TreeMap<>();

		for(int i = 0; i < n; i++) {
			int query = scan.nextInt();
			int a = scan.nextInt();

			switch(query) {

			case 0:	//insert
				if(!map.containsKey(a)) map.put(a, 1);
				else map.put(a, map.get(a) + 1);
				count++;
				System.out.println(count);
				break;

			case 1:	//find
				if(map.get(a) != null) System.out.println(map.get(a));
				else System.out.println(0);
				break;

			case 2:	//delete
				if(map.get(a) != null) {
					count -= map.get(a);
					map.remove(a);
				}
				break;

			case 3:	//dump
				int b = scan.nextInt();
				Map<Integer, Integer> subM = map.subMap(a,true, b,true);
				for(Integer x : subM.keySet()) {
					for(int j=0; j<map.get(x); j++) {
						System.out.println(x);
					}
				}
				break;
			}
		}
	}
}