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 make_divisors(n):
    divisors = []
    for i in range(1,int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n//i:
                divisors.append(n//i)

    return divisors
N = X -1
while(1):
    N +=1
    com = make_divisors(N)
    if len(com) == 2:
        ans = N
        break
print(ans)