#include <bits/stdc++.h>
#define ll long long
#define pi (acos(-1))
#define rep(i, n) for (unsigned long long i = 0; i < (unsigned long long)(n); ++i)
using namespace std;
std::vector<unsigned ll> genprimevec(const unsigned ll N);
int main()
{
    int h, w;
    cin >> h >> w;
    vector<int> v(h * w);
    rep(i, h * w) { cin >> v[i]; }
    sort(v.begin(), v.end());
    rep(i, h)
    {
        rep(j, w) { cout << v[(i * w) + j] << ' '; }
        cout << endl;
    }

    return 0;
}

/*author  https://qiita.com/drken/items/0c88a37eec520f82b788*/
ll extgcd(ll a, ll b, ll &x, ll &y)
{
    if (b == 0)
    {
        x = 1, y = 0;
        return a;
    }
    ll d = extgcd(b, a % b, y, x);
    y -= a / b * x;
    return d;
}


std::vector<unsigned ll> genprimevec(const unsigned ll N)
{
    std::vector<bool> is_prime(N + 1);
    for (unsigned ll i = 0; i <= N; i++) { is_prime[i] = true; }
    std::vector<unsigned ll> P;
    for (unsigned ll i = 2; i <= N; i++)
    {
        if (is_prime[i])
        {
            for (unsigned ll j = 2 * i; j <= N; j += i) { is_prime[j] = false; }
            P.emplace_back(i);
        }
    }
    return P;
}