#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = unsigned;
using u64 = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max()/32*15+208;

int main() {
    int h, w;
    cin >> h >> w;
    vector<int> v(h*w);
    for (auto &&i : v) scanf("%d", &i);
    sort(v.begin(),v.end());
    int cur = 0;
    for (int i = 0; i < h; ++i) {
        for (int j = 0; j < w; ++j) {
            if(j) printf(" ");
            printf("%d", v[cur++]);
        }
        puts("");
    }
    return 0;
}