#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b, long long* x, long long* y);
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  long long n;
  cin >> n;
  map<int, int> map;
  long long temp = n;
  long long count = 0;
  long long x, y;
  long long min = 1000000007;
  long long p = sqrt(n);
  x = p, y = p;
  long long req = n - p * p;
  if (req == 0) {
    cout << x + y << endl;
  } else if (req <= p)
    cout << x + y + 1 << endl;
  else {
    cout << x + y + 2 << endl;
  }
  return 0;
}
long long gcd(long long a, long long b, long long* x, long long* y) {
  if (a == 0) {
    *x = 0;
    *y = 1;
    return b;
  }
  long long x1, y1;
  long long g = gcd(b % a, a, &x1, &y1);
  *x = y1 - (b / a) * x1;
  *y = x1;
  return g;
}
