#include<iostream>
#include<stack>
using namespace std;
int main()
{
	stack<int> num;
	int a, s, b;
	cin>>a;
	for(int i=0;i<a;i++)
	{
		cin>>b;
		if(b==1)
			num.pop();
		else if(b==2)
			cout<<num.top()<<endl;
		else if(b==3){
		
			cin>>s;
			num.push(s);
	
		}
	}

  return 0;
}