Prime number 2 - MarisaOJ: Marisa Online Judge

Prime number 2

Time limit: 1000 ms
Memory limit: 256 MB
Determine whether or not given integer $n$ is a prime number. ### Input - An integer $n$. ### Output - `YES` if $n$ is a prime number, `NO` otherwise. ### Constraints - $0 \le n \le 10^{12}$. ### Example Input: ``` 7 ``` Output: ``` YES ```