# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def rotateRight(self, head: Optional[ListNode], k: int) -> Optional[ListNode]:
        if not head or k == 0:
            return head

        cur = head
        length = 0
        while(cur):
            length += 1
            prev = cur
            cur = cur.next
        else:
            prev.next = head # circular

        k = length - (k % length) # counterclockwise -> clockwise
        while(k > 0): # move k times (clockwise)
            k -= 1
            prev = head
            head = head.next
        else:
            prev.next = None  # tail
            return head # head