#include <iostream>
#include <queue>
using namespace std;
int main() {
ios::sync_with_stdio(false);
cin.tie(NULL);
priority_queue<int, vector<int>, greater<int>> pq;
int N;
cin >> N;
for (int i = 0; i < N; i++)
{
int tmp;
cin >> tmp;
if (tmp == 0)
{
if (pq.empty())
{
cout << 0 << '\n';
}
else
{
int tmp2 = pq.top();
cout << tmp2 << '\n';
pq.pop();
}
}
else
{
pq.push(tmp);
}
}
}
우선순위 큐를 알아보았어요~