Problem: Implement a stack using a singly linked list. The stack should support the following operations:

push$($int x$)$: Push an integer x onto the stack.

pop$()$: Remove and return the top element from the stack. If the stack is empty, return $-1.$

peek$()$: Return the top element of the stack without removing it$.$ If the stack is empty, return $-1.$

isEmpty$()$: Return True if the stack is empty, otherwise return False.