#include <bits/stdc++.h>
#include <cmath>
#include <bitset>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll  long long int
typedef tree<ll, null_type, less_equal<ll>, rb_tree_tag, tree_order_statistics_node_update> pbds;
#define lld long double
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define gcd(a, b) __gcd(a, b)
#define lcm(a, b) ((a * b) / gcd(a, b))
#define pi acos(-1.00)
const ll mod = 1e9+7;
const ll inf = 1e18+10;
inline void evan()
{
 ll n;cin>>n;
 ll ans=sqrtl(n);
 ll x=ans;
 ans+=(ans-1);
 if(x*(x+1)<=n)ans++;
 cout<<ans<<"\n";
 
}
signed main()
{
  ios_base::sync_with_stdio(false);  
  cin.tie(NULL);
  cout.tie(nullptr);
  ll t = 1;
//cin >> t;
 // cin.ignore();
  for (ll i = 1; i <= t; i++)
  {
    evan();
  }
}