PROGRAMMING:Prime judgment
Keyboard input a positive integer to determine whether the number is prime. Prime number is prime number, which can only be divided by 1 and itself. In particular, 1 is not a prime. If it is a prime, output "yes", otherwise output "no".
###Input format:
The input has only one use case, that is, an integer n.
###Output format:
If n is prime, output "yes", otherwise output "no".
###Input example:
```in
eleven
```
###Output example:
The corresponding output is given here. For example:
```out
YES
```
answer：If there is no answer, please comment
###Input format:
The input has only one use case, that is, an integer n.
###Output format:
If n is prime, output "yes", otherwise output "no".
###Input example:
```in
eleven
```
###Output example:
The corresponding output is given here. For example:
```out
YES
```
answer：If there is no answer, please comment