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 <bits/stdc++.h>
#define ll long long int 
using namespace std;
bool isprime(ll x)
{
    for(ll i=2;i*i<=x;i++)
    {
        if(x % i == 0)
            return false;
    }
    return true;
}
int main() 
{
  ll x;
  cin>>x;

  for(int i=x;i<=100003;i++)
  {
      if(isprime(i))
      {
          cout<<i;
          break;
      }
  }
}