PROGRAMMING:*Calculate factorial
Calculate factorial
Please write a program, input the integer $$n $, calculate and output the factorial of $$n $.
$$n! = 1 \times 2 \times 3 \times \cdots \times n$$
Where: $$0 / Leq n / Leq 20$$
####Input sample 1
```in
0
```
####Output sample 1
```out
one
```
####Input sample 2
```in
eighteen
```
####Output sample 2
```out
six thousand four hundred and two trillion and three hundred and seventy-three billion seven hundred and five million seven hundred and twenty-eight thousand
```
answer：If there is no answer, please comment
Please write a program, input the integer $$n $, calculate and output the factorial of $$n $.
$$n! = 1 \times 2 \times 3 \times \cdots \times n$$
Where: $$0 / Leq n / Leq 20$$
####Input sample 1
```in
0
```
####Output sample 1
```out
one
```
####Input sample 2
```in
eighteen
```
####Output sample 2
```out
six thousand four hundred and two trillion and three hundred and seventy-three billion seven hundred and five million seven hundred and twenty-eight thousand
```
answer：If there is no answer, please comment