#include <iostream>
#include<queue>
#include <vector>
using namespace std;

int main()
{
    priority_queue<int> pq;
    pq.push(10);
    pq.push(20);
    pq.push(30);

    while(!pq.empty()) {
        cout << pq.top() << " ";
        pq.pop();
    }
    cout << endl;

    return 0;
}