#include <iostream>
#include <queue>
#include <vector>
using namespace std;
const int N = 1e5 + 10;
priority_queue<int, vector<int>, greater<int>> cu_hp, ne_hp; //small heap, ne_hp stores nums ordered in next block

int n, m;
int main()
{
    ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
    cin >> n >> m;
    int cur_top;        //denote current heap top(smallest)
    int cnt = 0;        //control " " and endl in output 
    for (int i = 0; i < n; i++ ) {
        int x; cin >> x;    //cin n numbers
        if (i < m) {        
            cu_hp.push(x);      //directly put the first m numbers into heap
            if (i == m - 1) {   //currnt hp full for the first, record top value and print
                cur_top = cu_hp.top(); cu_hp.pop();
                if (cnt) cout << " ";
                cnt++ ;
                cout << cur_top;
            }
        }
        else {                  //the next (n - m) values need to be judged which heap to put
            if (x < cur_top) {ne_hp.push(x);}   //x is smaller than current heap top, so it shoule be put into next block
            else {
                cu_hp.push(x);  //x >= cur_top, so it can be put into current block
            }
            if (cu_hp.empty()) {    //no more nums can put into current block, this block finished
                swap(cu_hp, ne_hp); //it's time to focus on the next block, this meanwhile clear ne_hp at the same time
                cout << endl;
                cnt = 0;        //refresh output flag
            }
            cur_top = cu_hp.top(); cu_hp.pop();     //after i >= m-1, top value need to be printed
            if (cnt) cout << " ";
            cnt++;
            cout << cur_top;

        }
    }
    while (!cu_hp.empty()) {            //print remaining nums in current block(if exists)
        if (cnt) cout << " ";
        cnt++ ;
        cur_top = cu_hp.top(); cu_hp.pop();
        cout << cur_top;
    }
    cnt = 0;
    if (!ne_hp.empty()) cout << endl;   //print remaining nums in next block(if exists)
    while (!ne_hp.empty()) {
        if (cnt) cout << " ";
        cnt++ ;
        cur_top = ne_hp.top(); ne_hp.pop();
        cout << cur_top;
    }    
    return 0;
}