#include <bits/stdc++.h>
using namespace std;
const int maxn = (1 << 17) + 10;
const int inf = 0x3f3f3f3f;
const long long linf = 0x3f3f3f3f3f3f3f3f;
int main() {
  ios_base::sync_with_stdio(false);
  int x;
  cin >> x;
  if (x == 3) {
    cout << 5 << endl;
    return 0;
  }
  for (int i = 1; i <= 20; i += 2) {
    if ((i * (i - 1) / 2 + (i + 1) / 2) >= x) {
      cout << i << endl;
      break;
    }
  }
  return 0;
}
