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())
#n,m=map(int,input().split())
#pl=list(map(int,input().split()))
#l=[list(map(int,input().split())) for i in range(n)]
import math

while True:
    flag=True
    for i in range(2,int(math.sqrt(x))+1):
        if x%i==0:
            flag=False
            break    
    if flag:
        break
    else:
        x+=1
print(x)