Baekjoon #11279

#include<bits/stdc++.h>

using namespace std;

priority_queue<int> pq;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);

    int N; cin >> N;
    pq.push(0);
    for(int i=0;i<N;i++){
        int x;cin >> x;
        if(x == 0) {
            if(pq.empty()) cout << 0 << '\n';
            else { 
                cout << pq.top() << '\n';
                pq.pop();
            }
        }
        else pq.push(x);
    }

    return 0;
}

import sys
import heapq

def input():
    return sys.stdin.readline().rstrip()

N = int(input())
heap = []
for i in range(N):
    a = int(input())
    if a == 0:
        if heap:
            print(-heapq.heappop(heap))
        else:
            print(0)
    heapq.heappush(heap, -a)