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)

def judge_prime(num):
    FLAG = True
    
    for i in range(2, int(num**.5)+1):

        if (num%i == 0):
            FLAG = False
    
    if (num == 2):
        FLAG = True
    
    return(FLAG)

X = int(input())

while (True):
    flag = judge_prime(X)
    
    if (flag):
        break
    
    X += 1

print(X)