#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define fi first
#define se second
#define all(a) a.begin(),a.end()
int main(){
  int h,w;
  cin >> h >> w;
  vector<int> a(h*w);
  for(int &i:a) cin >> i;
  sort(all(a));

  for(int i=0; i<h; ++i){
    for(int j=0; j<w; ++j){
      cout << a[i*w+j];
      if(j<w-1) cout << " ";
      else cout << "\n";
    }
  }
  return 0;
}