#include <bits/stdc++.h>

using namespace std;

int main(){
    cin.tie(NULL)->sync_with_stdio(false);

    int n, k, v;
    cin >> n >> k;

    vector<int> ar(n);
    for(int i = 0; i < n; i++)
        cin >> ar[i];

    vector<bool> found(k + 1, false);
    vector<bool> last(n, false);

    for(int i = n - 1; i >= 0; i--){
        if(!found[ar[i]]){
            found[ar[i]] = true;
            last[i] = true;
        }
    }    

    int lb = 1;
    vector<bool> mex(k + 2, false);
    vector<int> stack;
    vector<int> result;

    mex[0] = true;

    for(int i = 0; i < n; i++){
        if(mex[ar[i]])
            continue;

        if(lb == ar[i]){
            stack.clear();
            result.push_back(ar[i]);
            
            mex[ar[i]] = true;
        }else if(lb < ar[i]){
            if(last[i]){
                int m_size = result.size();

                stack.push_back(ar[i]);

                for(int j = 0; j < stack.size(); j++){
                    while(result.size() > m_size && result.back() >= stack[j]){
                        mex[result.back()] = false;

                        result.pop_back();
                    }

                    mex[stack[j]] = true;

                    result.push_back(stack[j]);
                }

                stack.clear();
            }else{
                stack.push_back(ar[i]);
            }
        }

        while(mex[lb])
            lb++;
    }

    for(int &r : result)
        cout << r << " ";
    cout << "\n";
}