#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef pair<ll,ll> P;
typedef vector<P> vp;
typedef vector<string> vs;
typedef vector<bool> vb;

const ll mod=1e9+7;
const ll inf=1e16;

#define rep(i,m,n) for(ll i=m;i<n;i++)
#define repr(i,m,n) for(ll i=m-1;i>=n;i--)
#define f first
#define s second
#define chmax(x,y) x=max(x,y)
#define chmin(x,y) x=min(x,y)
#define eb(x) emplace_back(x)
#define pb(x) pop_back(x)
#define b back()
#define all(x) x.begin(),x.end()
#define allr(x) x.rbegin(),x.rend()
#define sum(x) accumulate(all(x),0)
#define pc(x) __builtin_popcount(x)
#define gll greater<ll>()


void solve(){
  ll h,w;
  cin >> h >> w;
  vll a(h*w);

  rep(i,0,h*w) cin >> a[i];
  
  
    sort(all(a));
  rep(i,0,h){
   rep(j,0,w-1) cout << a[i*w+j] << " "; 
    cout << a[i*w+(w-1)] << endl;
  }
   
  
  
  
}
int main(){
   cin.tie(nullptr);
  ios::sync_with_stdio(false);
  solve();
}