#include <bits/stdc++.h>
#define rep(i, ss, ee) for (int i = ss; i < ee; ++i)
using namespace std;

void solve() {
  int H, W;
  cin >> H >> W;
  vector<int> v(H * W);
  rep(i, 0, H * W) { cin >> v[i]; }
  sort(v.begin(), v.end());

  int i = 0;
  for (auto e : v) {
    cout << ((i == 0) ? "" : " ") << e;
    if (i == W - 1) {
      cout << endl;
      i = 0;
    } else {
      i++;
    }
  }
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  solve();
  getchar();
}