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: Accepted)

x = int(input())


def prime(n):
    flag = ''
    for i in range(2, int(n ** 0.5) + 1):
        if n % i == 0:
            break
    else:
        flag = 'prime_number'

    return(flag)


if x == 2:
    print(2)
else:
    i = x + int(x % 2 == 0)

    while(True):
        if prime(i) == 'prime_number':
            break

        i += 1

    print(i)