#include <bits/stdc++.h>
using namespace std;
int main(){
int n,x,num;
cin>>n;
stack<int> st;
while(n--){
cin>>num;
switch(num)
{
case 1: st.pop(); break;
case 2: cout<<st.top()<<endl; break;
case 3: cin>>x; st.push(x); break;
}
}

}