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++ (GCC 9.2.1) (judge verdict: Accepted)

#include "bits/stdc++.h"
using ll = long long;
using namespace std;

bool isPrime(int x) {
   for(int i = 2; i < x; i++) {
      if(x % i == 0)
      return false;
   }
   return true;
}
void solve() {
   int x;
   cin >> x;
   for(int i = x; ; i++) {
      if(isPrime(i)) {
         cout << i << endl;
         return;
      }
   }
}

int main() {
   cin.tie(0);
   cin.sync_with_stdio(0);
   int testcase = 1;
   // cin >> testcase;
 
   for(int i = 0; i < testcase; i++) {
      solve();
   } 
   return 0;
}