#include <bits/stdc++.h>
#define rep(i,s,n) for (int i = s; i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int,int>;
using field = vector<vector<int>>;

int main() {
  int h,w;
  cin >> h >> w;
  vector<int> a(h*w);
  rep(i,0,h*w) cin >> a[i];
  sort(a.begin(), a.end());
  rep(i,0,h) {
    rep(j,0,w) {
      cout << a[i*w+j] << " ";
    }
    cout << "\n";
  }
  return 0;
}