/** gnu specific **/
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
/** contains everything I need in std **/
#include <bits/stdc++.h>

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(S) ((int)S.size())
#define FOR(i, st_, n) for(int i = st_; i < n; ++i)
#define RFOR(i, n, end_) for(int i = (n)-1; i >= end_; --i)
#define x first
#define y second
#define pb push_back
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef pair<double, double> pdd;
typedef unsigned long long ull;
typedef long double LD;
typedef pair<ull, ull> pull;
using namespace __gnu_pbds;
typedef tree<ll, null_type, less<>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
using namespace std;
#ifdef ONPC
mt19937 rnd(228);
#else
mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
#endif

// sparse table with or binary operation
class SparseTable
{
public:
    std::vector<std::vector<ll>> table;
    std::vector<ll> log2;
    
    SparseTable() {}

    SparseTable(const std::vector<ll>& arr)
    {
        int n = arr.size();
        int max_log = std::log2(n) + 1;

        table.resize(n, std::vector<ll>(max_log));
        log2.resize(n + 1);

        log2[1] = 0;
        for (int i = 2; i <= n; ++i) {
            log2[i] = log2[i / 2] + 1;
        }

        for (int i = 0; i < n; ++i) {
            table[i][0] = arr[i];
        }

        for (int j = 1; j < max_log; ++j) {
            for (int i = 0; i + (1 << j) <= n; ++i) {
                table[i][j] = min(table[i][j - 1], table[i + (1 << (j - 1))][j - 1]);
            }
        }
    }

    ll query(int L, int R) {
        int j = log2[R - L + 1];
        return min(table[L][j], table[R - (1 << j) + 1][j]);
    }
};

int solve()
{
	int n,k;
	if(!(cin>>n>>k))return 1;
	vector<ll> a(n);
	vector<int> c(k+1,0);
	FOR(i,0,n)cin>>a[i],c[a[i]]+=1;
	a.pb(k+1);
	SparseTable st(a);
	vector<int>res;
	vector<bool> in(n+1,false);
	for(int l=0,r=0; l<n;)
	{
		r=max(l,r);
		while(r<n && c[a[r]] > 1)
		{
			c[a[r]]-=1;
			++r;
		}
		int mVal = st.query(l,r);
		while(a[l]!=mVal)++l;
		if(!in[mVal])in[mVal]=true,res.pb(mVal);
		++l;
	}
	//assert(sz(res)==k);
	for(auto item:res)cout<<item<<' ';
	cout<<'\n';
    return 0;
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    int TET = 1e9;
    //cin >> TET;
    for (int i = 1; i <= TET; i++)
    {
        if (solve())
        {
            break;
        }
#ifdef ONPC
        cout << "__________________________" << endl;
#endif
    }
#ifdef ONPC
    cerr << endl << "finished in " << clock() * 1.0 / CLOCKS_PER_SEC << " sec" << endl;
#endif
}