Write an expression that executes the loop while the user enters a number greater than or equal to 0. Note: These activities may test code with different test values. This activity will perform three tests, with userNum initially 9 and user input of 5, 2, -1, then with userNum initially 0 and user input of -17, then with userNum initially -1. See "How to Use zyBooks". Also note: If the submitted code has an infinite loop, the system will stop running the code after a few seconds, and report "Program end never reached." The system doesn't print the test case that caused the reported message.