#include <bits/stdc++.h>

using namespace std;

typedef long long LL;

const int nmax = 200010; const LL mod = 1000000007;

int N,v[nmax],M;
char ch[1000];
char x1,x2;

int main(void){
   LL i,j,urm,x,cnt,w;
//   freopen("txt.in","r",stdin);
//   freopen("txt.out","w",stdout);
//   ios::sync_with_stdio(false);
   cin >> N >> M;
   i = 1;
   while(cin >> ch){
      int lg = strlen(ch);
      for(j = 1; j < lg-1; j+=2){
         x1 = ch[j];
         x2 = ch[j+1];
         if(x1 == x2)
            continue;
         if(x1 < x2)
            ch[j+1] = x1;
         else
            ch[j] = x2;
      }
      for(j = 0; j < lg; j+=2)
         cout << ch[j];
      if(i%M==0)
         cout << '\n';
      else cout <<' ';
      ++i;
   }
    return 0;
}