E. Colors and Intervalstime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputThe numbers 1, \, 2, \, \dots, \, n \cdot k are colored with n colors. These colors are indexed by 1, \, 2, \, \dots, \, n. For each 1 \le i \le 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, \, \dots, \, b\}. You must choose n intervals [a_1, \, b_1], \, [a_2, \, b_2], \, \dots, [a_n, \, b_n] such that:   for each 1 \le i \le n, it holds 1 \le a_i < b_i \le n \cdot k;  for each 1 \le i \le n, the numbers a_i and b_i are colored with color i;  each number 1 \le x \le n \cdot k belongs to at most \left\lceil \frac{n}{k - 1} \right\rceil intervals. One can show that such a family of intervals always exists under the given constraints.InputThe first line contains two integers n and k (1 \le n \le 100, 2 \le k \le 100) — the number of colors and the number of occurrences of each color.The second line contains n \cdot k integers c_1, \, c_2, \, \dots, \, c_{nk} (1 \le c_j \le n), where c_j is the color of number j. It is guaranteed that, for each 1 \le i \le n, it holds c_j = i for exactly k distinct indices j.OutputOutput 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.ExamplesInput
4 3
2 4 3 1 1 4 2 3 2 1 3 4
Output
4 5
1 7
8 11
6 12Input
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 4Input
2 3
2 1 1 1 2 2
Output
2 3
5 6
NoteIn the first sample, each number can be contained in at most \left\lceil \frac{4}{3 - 1} \right\rceil = 2 intervals. The output is described by the following picture:  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\lceil \frac{1}{2 - 1} \right\rceil = 1 interval.In the third sample, each number can be contained in at most \left\lceil \frac{3}{3 - 1} \right\rceil = 2 intervals. The output is described by the following picture:  
4 3
2 4 3 1 1 4 2 3 2 1 3 4

4 5 1 7 8 11 6 12
['constructive algorithms', 'data structures', 'greedy', 'sortings', '*2300']