Given a Stack of integers and a target value, if the target value exists somewhere in the stack, push the target value's 1-based index onto the top of the stack and return the stack. The 1-based index means that if the target value is on the top of the stack already, push a 1. If it is the second element in the stack, then push a 2. If the target value does not exist in the stack, push a -1 to the top of the stack.

YOUR FIRST TWO LINES OF CODE MUST BE:
Stack<Integer> stack = new Stack<Integer>();
stack.addAll(list);