#include <bits/stdc++.h>
using namespace std;
struct edge {
  int u, v;
  long long w;
};
long long MOD = 1000000007;
long long _MOD = 1000000009;
int INF = INT_MAX / 10;
double EPS = 1e-10;
double PI2 = M_PI * 2;
int main() {
  int x;
  cin >> x;
  if (x == 3) {
    cout << 5 << endl;
    return 0;
  }
  int n;
  for (n = 1; (n * n + 1) / 2 < x; n += 2)
    ;
  cout << n << endl;
}
