#include <iostream>
using namespace std;
#include <stack>
#include <vector>
int main() {
	//用栈存储货物
	stack<int> s;
	//数组记录最重货物
	vector<int> v;
	int maxW = 0;
	int weight = 0;
	int n;
	int op;
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> op;

		switch (op)
		{
		case 0:
			cin >> weight;
			s.push(weight);
			v.push_back(weight);
			break;
			
		case 1:
			s.pop();
			v.pop_back();
			break;

		case 2:
			if (s.empty()) {
				cout << 0;
			}
			else {
				for (auto eliment : v) {
					if (eliment > maxW) maxW = eliment;
				}
				cout << maxW;
				maxW = 0;
			}
			break;
		default:
			break;
		}


	}
}