#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
long long int n, val = INT_MAX, m, k;
vector<long long int> v;
long long int ar[101][101];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long int i, j, x;
  cin >> x;
  if (x == 3) {
    cout << "5\n";
    return 0;
  } else if (x == 1) {
    cout << "1\n";
    return 0;
  } else if (x <= 5) {
    cout << "3\n";
    return 0;
  }
  long long int low = 5, high = 1e7 + 1;
  while (low < high) {
    long long int mid = (low + high) / 2;
    mid -= (mid % 2 == 0);
    if ((mid * mid + 1) / 2 >= x)
      high = mid;
    else
      low = mid + 2;
  }
  high -= (high % 2 == 0);
  cout << high << "\n";
  return 0;
}
