ehhhh

#include <bits/stdc++.h>
int n, k;
std::queue<int> q;
std::set<int> cur;
int main(){
    std::cin >> n >> k;
    for(int i =0 ;i < n; i++){
        int id;
        std::cin >> id;
        if(!cur.count(id)){
            if((int)(q.size()) >= k){
                int x = q.front();
                q.pop();
                cur.erase(x);
            }
            cur.insert(id);
            q.push(id);
        }
    }
    std::vector<int> ans;
    while(!q.empty()){
        ans.push_back(q.front());
        q.pop();
    }
    reverse(ans.begin(), ans.end());
    std::cout << ans.size() << std::endl;
    for(auto i : ans){
        std::cout << i << " ";
    }
    std::cout << std::endl;
}