#include <bits/stdc++.h>
using namespace std;
int x;
int main() {
  ios_base ::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> x;
  if (x == 3) {
    cout << 5 << endl;
    return 0;
  }
  for (int i = 1; i <= 199; i += 2) {
    int temp = i * i + 1;
    temp /= 2;
    if (temp >= x) {
      cout << i << endl;
      break;
    }
  }
  return 0;
}
