/**

 * Definition for singly-linked list.

 * public class ListNode {

 *     int val;

 *     ListNode next;

 *     ListNode(int x) { val = x; }

 * }

 */

class Solution {

    public ListNode removeNthFromEnd(ListNode head, int n) {

        ListNode dummy=new ListNode(0);

        dummy.next=head;

        ListNode first=head;

        int lenght=0;

        while(first!=null)

        {

            first=first.next;

            lenght++;

        }

        lenght=lenght-n;

        first=dummy;

        while(lenght>0)

        {

            lenght--;

            first=first.next;

        }

        first.next=first.next.next;

        return dummy.next;

    }

}