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 Julia (0.5.0) (judge verdict: Wrong Answer)

function isprime(x)
    if x<=1
        return false
    end
    rootx = ceil(sqrt(x))
    for i =2:rootx
        if x%i==0
            return false
        end
    end
    return true
end

x1 = parse(Int64, readline())
# println(x1)
p = x1
# println(p)

while (!isprime(p))
    global p += 1
end
println(p)