#include <bits/stdc++.h>

using namespace std;

int main() {
  int N;
  scanf("%d", &N);

  int start = N - 100 < 3? 3: N - 100;
  for (int i = start; i <= N + 100; ++i) {
    if (i % 2 == 0) {
      printf("%d\n", i);
      break;
    }
  }
  return 0;
}