#include <iostream>

using namespace std;

int *a, *b;
int s, t;

void push(int x)
{
	s++;

	if (s > t)
	{
		t *= 2;

		b = new int[t];

		for (int i = 0; i < s; i++)
		{
			b[i] = a[i];
		}

		int *c = a;
		a = b;
		delete c;
	}

	a[s] = x;
}

int pop() {
	int res = a[s];

	if ((t > 4*s) && (t > 23))
	{
		t /= 2;

		b = new int[t];

		for (int i = 0; i < s; i++)
		{
			b[i] = a[i];
		}

		int *c = a;
		a = b;
		delete c;
	}

	s--;

	return res;
}

int main()
{
    int n, x;
	char c;

	freopen("stack1.in", "r", stdin);
	freopen("stack1.out", "w", stdout);

	scanf("%d\n", &n);

	s = -1;
	t = 23;

	a = new int[t];

	for (int i = 0; i < n; i++)
	{
		scanf("%c", &c);
		if (c == '+')
		{
			scanf("%d\n", &x);
			push(x);
		} else
		{
			printf("%d\n", pop());
			scanf("\n");
		}
	}
	return 0;
}