Problem:
Score: 300 points

Problem Statement

Find the minimum prime number greater than or equal to X.

Notes

A prime number is an integer greater than 1 that cannot be evenly divided by any positive integer except 1 and itself.

For example, 2, 3, and 5 are prime numbers, while 4 and 6 are not.

Constraints

2 \le X \le 10^5

All values in input are integers.

Input

Input is given from Standard Input in the following format:

X

Output

Print the minimum prime number greater than or equal to X.

Sample Input 1

20

Sample Output 1

23

The minimum prime number greater than or equal to 20 is 23.

Sample Input 2

2

Sample Output 2

2

X itself can be a prime number.

Sample Input 3

99992

Sample Output 3

100003

Solution in Python (3.4.3) (judge verdict: Runtime Error)

def resolve():
    def is_prime(n):
        if n == 1:
            return False

        for k in range(2, int(math.sqrt(n)) + 1):
            if n % k == 0:
                return False

        return True
    X = int(input())

    while True:
        if is_prime(X):
            print(X)
            return
        else:
            X += 1

    return
  
  
resolve()