B'The numbers 1, , 2, , ... , , n cdot 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: One can show that such a family of intervals always exists under the given constraints. 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 cdot 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 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. In the first sample, each number can be contained in at most <= ft 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 <= ft lceil frac{1}{2 - 1} right rceil = 1 interval. In the third sample, each number can be contained in at most <= ft lceil frac{3}{3 - 1} right rceil = 2 intervals. The output is described by the following picture: '...