Create Prime Number?

Problem Description
Write a function to check whether n is a prime number

int is_prime(int n)

Return a value different from zero if indeed n is a prime number. Zero otherwise.

1 <= n <= 2147483647

Input
The input will consist of a series of integer n, one integers per line.

Output
yes or no

Sample Input
10
2
971
Sample Output
no
yes
yes