#include <bits/stdc++.h>
using namespace std;
inline int toInt(string s) {
  int v;
  istringstream sin(s);
  sin >> v;
  return v;
}
template <class T>
inline string toString(T x) {
  ostringstream sout;
  sout << x;
  return sout.str();
}
const double EPS = 1e-10;
const double PI = acos(-1.0);
int main() {
  int x;
  cin >> x;
  int temp;
  for (int i = 1; i < 30; i += 2) {
    if (((i * i + 1) / 2) >= x) {
      temp = i;
      break;
    }
  }
  if (x == 3)
    cout << 5 << endl;
  else
    cout << temp << endl;
}
