#include <iostream>

using namespace std;

typedef int ElemType;

typedef struct LNode
{
    ElemType data;
    LNode* link;
}LNode, *LinkList;

LNode* search_k(LinkList& list, int k)
{
    LNode* slow = new(LNode);
    LNode* fast = new(LNode);
    slow = fast = list->link;

    while (fast != NULL && k > 1)
    {
        fast = fast->link;
        k -- ;
    }

    if (fast == NULL) return fast; // 不够k个结点

    while (fast->link != NULL)
    {
        slow = slow->link;
        fast = fast->link;
    }

    return slow;
}

int main()
{
    LinkList list = new(LNode);  // 初始化链表 1->2->3->4->5->6->7->8->9->10
    list->link = NULL;
    for (int i = 10; i >= 1; i -- ) // 头插法
    {
        LNode* p = new(LNode);
        p->data = i;
        p->link = list->link;
        list->link = p;
    }

    int k;
    cin >> k;

    if (search_k(list, k)) cout << search_k(list, k)->data << endl;
    else cout << "失败, 结点数不够" << k << "个" << endl;
    return 0;

}