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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <vector>

#define ll long long 

using namespace std;

bool isPrime(int n) 
{ 

    if (n <= 1) 
        return false; 
  
    
    for (int i = 2; i < n; i++) 
        if (n % i == 0) 
            return false; 
  
    return true; 
} 

int main(){
    int x;
    cin >> x;
    if(isPrime(x)){
        x = x;
    }
    else{
        
        while(!isPrime(x)){
            x = x + 1;
        }
    }
    cout << x;
}