#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  long long n;
  cin >> n;
  if (n == 1) {
    cout << "1\n";
    return 0;
  }
  if (n == 3) {
    cout << "5\n";
    return 0;
  }
  n *= 2;
  n -= 1;
  long long val = ceil(double(sqrt(n)));
  cout << ((val % 2 == 0) ? val + 1 : val) << "\n";
  return 0;
}
