#include <algorithm>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;

typedef long long ll;

#define MOD 1000000007

int main() {
  int n;
  cin >> n;
  for (int m = n - 100; m <= n + 100; ++m) {
    bool ok = false;
    for (int i = 2; i * i <= m; ++i) {
      if (m % i == 0) ok = true;
    }
    if (ok) {
      cout << m << endl;
      return 0;
    }
  }
  return 0;
}