The numbers 1,   2,   ...,   n ⋅ k are colored with n colors. These colors are indexed by 1,   2,   ...,   n. For each 1 ≤ i ≤ n, there are exactly k numbers colored with color i.

Let [a,   b] denote the interval of integers between a and b inclusive, that is, the set \\{a,   a + 1,   ...,   b\}. You must choose n intervals [a_1,   b_1],   [a_2,   b_2],   ..., [a_n,   b_n] such that: 

  * for each 1 ≤ i ≤ n, it holds 1 ≤ a_i < b_i ≤ n ⋅ k; 
  * for each 1 ≤ i ≤ n, the numbers a_i and b_i are colored with color i; 
  * each number 1 ≤ x ≤ n ⋅ k belongs to at most \left⌈ (n)/(k - 1) \right⌉ intervals. 



One can show that such a family of intervals always exists under the given constraints.

Input

The first line contains two integers n and k (1 ≤ n ≤ 100, 2 ≤ k ≤ 100) — the number of colors and the number of occurrences of each color.

The second line contains n ⋅ k integers c_1,   c_2,   ...,   c_{nk} (1 ≤ c_j ≤ n), where c_j is the color of number j. It is guaranteed that, for each 1 ≤ i ≤ n, it holds c_j = i for exactly k distinct indices j.

Output

Output n lines. The i-th line should contain the two integers a_i and b_i.

If there are multiple valid choices of the intervals, output any.

Examples

Input


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


Output


4 5
1 7
8 11
6 12

Input


1 2
1 1


Output


1 2


Input


3 3
3 1 2 3 2 1 2 1 3


Output


6 8
3 7
1 4

Input


2 3
2 1 1 1 2 2


Output


2 3
5 6

Note

In the first sample, each number can be contained in at most \left⌈ (4)/(3 - 1) \right⌉ = 2 intervals. The output is described by the following picture:

<image>

In the second sample, the only interval to be chosen is forced to be [1,   2], and each number is indeed contained in at most \left⌈ (1)/(2 - 1) \right⌉ = 1 interval.

In the third sample, each number can be contained in at most \left⌈ (3)/(3 - 1) \right⌉ = 2 intervals. The output is described by the following picture:

<image>
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author lucasr
 */
public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		MyScanner in = new MyScanner(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		EColorsAndIntervals solver = new EColorsAndIntervals();
		solver.solve(1, in, out);
		out.close();
	}

	static class EColorsAndIntervals {
		public static MyScanner sc;
		public static PrintWriter out;

		public void solve(int testNumber, MyScanner sc, PrintWriter out) {
			EColorsAndIntervals.sc = sc;
			EColorsAndIntervals.out = out;
			int n = sc.nextInt();
			int k = sc.nextInt();
			IntArray[] pos = new IntArray[n];
			for (int i = 0; i < n; i++) {
				pos[i] = new IntArray();
			}
			for (int i = 1; i <= n * k; i++) {
				int color = sc.nextInt() - 1;
				pos[color].add(i);
			}
			int from = 0;
			int[] resA = new int[n], resB = new int[n];
			boolean[] used = new boolean[n];
			while (from < n) {
				int to = Math.min(from + k - 1, n);
				int ops = to - from;
				for (int end = 1; end < k && end <= ops; end++) {
					int min = -1;
					for (int i = from; i < to; i++)
						if (!used[i]) {
							if (min == -1 || pos[i].get(end) < pos[min].get(end)) {
								min = i;
							}
						}
					resA[min] = pos[min].get(end - 1);
					resB[min] = pos[min].get(end);
					used[min] = true;
				}
				from += k - 1;
			}
			for (int i = 0; i < n; i++) {
				out.println(resA[i] + " " + resB[i]);
			}
		}

	}

	static class IntArray {
		int[] arr;
		int size;

		public IntArray() {
			arr = new int[4];
		}

		public void add(int val) {
			if (size == arr.length) {
				arr = Arrays.copyOf(arr, 2 * arr.length);
			}
			arr[size++] = val;
		}

		public int get(int pos) {
			return arr[pos];
		}

		public int[] toArray() {
			return Arrays.copyOf(arr, size);
		}

		public String toString() {
			return "IntArray " + Arrays.toString(toArray());
		}

	}

	static class MyScanner {
		private BufferedReader br;
		private StringTokenizer tokenizer;

		public MyScanner(InputStream is) {
			br = new BufferedReader(new InputStreamReader(is));
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

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

	}
}

