#include <iostream>
#include <algorithm>
#include <set>
#include <stdio.h>
using namespace std;

int main()
{
    int n, x,j = 0;
    char c;

    cin >> n;
    multiset <int> a;
    for (int i = 0; i < 2 * n; i++)
    {
        cin >> c;
        if (c == '+'){
            scanf("%d", &x);
            a.insert(x);

        }
        if (c == '?'){
            printf("%d \n" , *a.begin());
            a.erase(a.begin());


        }


    }

    return 0;
}