Let's call an undirected graph of n vertices p-interesting, if the following conditions fulfill: 

  * the graph contains exactly 2n + p edges; 
  * the graph doesn't contain self-loops and multiple edges; 
  * for any integer k (1 ≤ k ≤ n), any subgraph consisting of k vertices contains at most 2k + p edges. 



A subgraph of a graph is some set of the graph vertices and some set of the graph edges. At that, the set of edges must meet the condition: both ends of each edge from the set must belong to the chosen set of vertices. 

Your task is to find a p-interesting graph consisting of n vertices.

Input

The first line contains a single integer t (1 ≤ t ≤ 5) — the number of tests in the input. Next t lines each contains two space-separated integers: n, p (5 ≤ n ≤ 24; p ≥ 0; <image>) — the number of vertices in the graph and the interest value for the appropriate test. 

It is guaranteed that the required graph exists.

Output

For each of the t tests print 2n + p lines containing the description of the edges of a p-interesting graph: the i-th line must contain two space-separated integers ai, bi (1 ≤ ai, bi ≤ n; ai ≠ bi) — two vertices, connected by an edge in the resulting graph. Consider the graph vertices numbered with integers from 1 to n. 

Print the answers to the tests in the order the tests occur in the input. If there are multiple solutions, you can print any of them.

Examples

Input

1
6 0


Output

1 2
1 3
1 4
1 5
1 6
2 3
2 4
2 5
2 6
3 4
3 5
3 6
//package CF;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.Queue;
import java.util.StringTokenizer;

public class A {
    public static void main(String[] args) throws Exception
    {
	Scanner bf = new Scanner(System.in);
	PrintWriter out = new PrintWriter(System.out);
	int t = bf.nextInt();
	while(t-->0)
	{
	    int n = bf.nextInt(), p = bf.nextInt();
	    int num = 0;
	    loop:
	    for (int i = 1; i <= n; i++)
	    {
		for (int j = i+1; j <= n; j++)
		{
		    out.println(i + " " + j);
		    num++;
		    if(num == 2*n+p)
			break loop;
		}
	    }
	}
	out.flush();
	out.close();
    }

    static class Scanner {
	StringTokenizer st;
	BufferedReader br;

	public Scanner(InputStream s)
	{
	    br = new BufferedReader(new InputStreamReader(s));
	}

	public Scanner(FileReader fileReader)
	{
	    br = new BufferedReader(fileReader);
	}

	public String next() throws IOException
	{
	    while (st == null || !st.hasMoreTokens())
		st = new StringTokenizer(br.readLine());
	    return st.nextToken();
	}

	public int nextInt() throws IOException
	{
	    return Integer.parseInt(next());
	}

	public long nextLong() throws IOException
	{
	    return Long.parseLong(next());
	}

	public String nextLine() throws IOException
	{
	    return br.readLine();
	}

	public boolean ready() throws IOException
	{
	    return br.ready();
	}
    }
}