#include <iostream>
#include <cstdio>
using namespace std;
struct lb
{
    int n;
    lb *next;
};
lb *p, *t, *r, *p2;
void find(int n)
{
    p = t;
    for (; p->next != NULL; p = p->next)
    {
        if (p->n == n)
        {
            return;
        }
    }
}
int main()
{
    t = new lb;
    t->n = 1;
    t->next = NULL;
    r = t;
    int n;
    cin >> n;
    int x, y, z;
    for (int i = 1; i <= n; i++)
    {
        cin >> x;
        switch (x)
        {
        case 1:
        {
            cin >> y >> z;
            find(y);
            p2 = new lb;
            p2->n = z;
            p2->next = p->next;
            p->next = p2;
            break;
        }
        case 2:
        {
            cin >> y;
            find(y);
            if (p->next == NULL)
            {
                printf("0\n");
            }
            else
            {
                printf("%d\n", p->next->n);
            }
            break;
        }
        case 3:
        {
            cin >> y;
            find(y);
            p->next = p->next->next;
            break;
        }
        }
    }
    return 0;
}

不出意外的超时了，80分