#include <iostream>
using namespace std;
int main(){
    int array[110];
    int size = 0;
    int n;
    cin >> n;
    int num = 0;
    int type = 0;
    for(int i = 0;i<n;i++){
        cin >> type >> num;
        if(type==1){
            array[size++] = num;
        }
        if(type==2){
            if(size==0){
                cout<<-1<<endl;
                continue;
            }
            cout<<array[0]<<endl;
        }
        if(type==3){
            if(size==0){
                continue;
            }
            for(int i =1;i<size;i++){
                array[i-1] = array[i];
            }
            size--;
        }
    }
    return 0;
}