/*------------------------------------------------------------------------------
 * find_mth_to_the_last.c: 
**----------------------------------------------------------------------------*/

/* Copyright (c) 2009 Peter Bui. All Rights Reserved.
 *
 * Peter Bui <pbui@cse.nd.edu>
 *
**------------------------------------------------------------------------------
 * Includes
**----------------------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>

/*------------------------------------------------------------------------------
 * Type Definitions
**----------------------------------------------------------------------------*/

struct slist_node {
    int	    data;
    struct  slist_node *next;
};

/*------------------------------------------------------------------------------
 * Functions
**----------------------------------------------------------------------------*/

struct slist_node *
slist_node_alloc(int data)
{
    struct slist_node *sn_next;

    sn_next = malloc(sizeof(struct slist_node));
    sn_next->data = data;
    sn_next->next = NULL;

    return (sn_next);
}

struct slist_node *
slist_node_append(struct slist_node *sn, int data)
{
    struct slist_node *sn_next;

    sn_next  = slist_node_alloc(data);
    sn->next = sn_next;

    return (sn_next);
}

struct slist_node *
find_mth_to_the_last(struct slist_node *sn_head, int mth)
{
    int i;
    struct slist_node *sn_mth = NULL, *sn_next;

    sn_mth = sn_next = sn_head;

    for (i = 0; i < mth && sn_next; i++)
	sn_next = sn_next->next;

    if (!sn_next) 
	return ((i < mth) ? NULL : sn_mth);

    while (sn_next->next) {
	sn_next = sn_next->next;
	sn_mth  = sn_mth->next;
    }

    return (sn_mth);
}

/*------------------------------------------------------------------------------
 * Main Execution
**----------------------------------------------------------------------------*/

int
main(int argc, char* argv[]) 
{
    int data, mth;
    struct slist_node *sn_head = NULL, *sn_next = NULL, *sn_mth = NULL;

    while (scanf("%d", &data) && data >= 0) {
	if (!sn_head) 
	    sn_next = sn_head = slist_node_alloc(data);
	else
	    sn_next = slist_node_append(sn_next, data);
    }

    while (scanf("%d", &mth) != EOF) {
	sn_mth = find_mth_to_the_last(sn_head, mth);
	printf("%d\n", (sn_mth) ? sn_mth->data : -1);
    }

    return (EXIT_SUCCESS);
}

/*------------------------------------------------------------------------------
 * vim: sts=4 sw=4 ts=8 ft=c
**----------------------------------------------------------------------------*/