Chapter 7, Problem 2DE

Why does the following pseudocode not perform as indicated in the comments?

// This program gets a dollar amount from the user

// and validates the input.

Declare Real amount

// Get the amount from the user.

Display "Enter a dollar amount"

Input amount

// Make sure the amount is not less than zero. If it is,

// get a new amount from the user.

While amount < 0

Display "ERROR: The dollar amount cannot be less than 0."

Display "Enter a dollar amount."

End While