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 PyPy3 (2.4.0) (judge verdict: Accepted)

X = int(input())
def primes(N):
    P = []
    for i in range(2,N):
        sieve = 1
        for p in P:
            if p*p > i:
                break
            elif i % p == 0:
                sieve = 0
                break
        if sieve == 0:
            continue
        else:
            P.append(i)
    return P

P = primes(X)
y = X
while True:
    for p in P:
        if y % p == 0:
            break
    else:
        break
    y += 1
    continue
print(y)