#include <bits/stdc++.h>
using namespace std;
int main() {
  int N;
  cin >> N;
  if (N == 1) {
    cout << 1;
    return 0;
  }
  if (N == 2) {
    cout << 3;
    return 0;
  }
  if (N == 3) {
    cout << 5;
    return 0;
  }
  if (N == 4) {
    cout << 3;
    return 0;
  }
  if (N == 5) {
    cout << 3;
    return 0;
  }
  if (N == 6) {
    cout << 5;
    return 0;
  }
  int k = int(sqrt(2 * (N - 1)));
  ++k;
  k = k + (k + 1) % 2;
  cout << k;
  return 0;
}
