#include <bits/stdc++.h>
using namespace std;
const int N = 110005;
const int mod = 1e9 + 7;
int ans;
int main() {
  int x;
  cin >> x;
  int z = x;
  while (x) {
    int y;
    if (x % 2 == 0) {
      y = x * (x / 2);
    } else {
      y = (x / 2) * (x / 2) + ((x + 1) * (x + 1)) / 4;
    }
    if (y >= z) ans = x;
    x--;
  }
  if (z == 3 || z == 2) ans = 5;
  if (z == 2) ans = 3;
  if (ans % 2 == 0) ans++;
  cout << ans;
}
