In mathematics, the notation n$!$ represents the factorial of the nonnegative integer n$.$ The factorial of n is the product of all the nonnegative integers from $1$ to n$.$ For example:

$7!=1$ x $2$ x $3$ x $4$ x $5$ x $6$ x $7=5,040$

Write a program that lets the user enter a nonnegative integer and then uses a loop to calculate the factorial of that number. Display the factorial.

Look carefully at the following sample run of the program. In particular, notice the wording of the message and the placement of spaces and colons. Your program's output must match this.