#include <cmath>
#include <iostream>
using namespace std;
bool isComposite(int n) {
  if (n <= 1) {
    return false;
  }
  if (n <= 3) {
    return false;
  }
  if (n % 2 == 0 || n % 3 == 0) {
    return true;
  }
  int i = 5;
  while (i * i <= n) {
    if (n % i == 0 || n % (i + 2) == 0) {
      return true;
    }
    i = i + 6;
  }
  return false;
}
int getSum(int n) {
  int s = 0;
  while (n > 0) {
    s += n % 10;
    n /= 10;
  }
  return s;
}
int getPrimeSum(int n) {
  int s = 0;
  while (n % 2 == 0) {
    s += 2;
    n /= 2;
  }
  for (int i = 3; i <= sqrt(n); i += 2) {
    while (n % i == 0) {
      s += getSum(i);
      n /= i;
    }
  }
  if (n > 2) {
    s += getSum(n);
  }
  return s;
}
int main() {
  int n;
  cin >> n;
  while (true) {
    if (getSum(n) == getPrimeSum(n)) {
      if (getPrimeSum(n) != 0) {
        if (isComposite(n)) {
          break;
        }
      }
    }
    n += 1;
  }
  cout << n << endl;
  return 0;
}