/**

 * Definition for singly-linked list.

 * public class ListNode {

 *     int val;

 *     ListNode next;

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

 * }

 */

class Solution {

    public ListNode insertionSortList(ListNode head) {

        ListNode helper=new ListNode(-1);

        ListNode cur=helper;

        while(head!=null){

            ListNode next=head.next;

            cur=helper;

            while(cur.next!=null&&cur.next.val<=head.val){

                cur=cur.next;

            }

            head.next=cur.next;

            cur.next=head;

            head=next;

        }

        return helper.next;

    }

}