#include <bits/stdc++.h>
using namespace std;
bool is_prime(int n) {
  if (n == 1) {
    return false;
  }
  int i = 2;
  while (i * i <= n) {
    if (n % i == 0) {
      return false;
    }
    i += 1;
  }
  return true;
}
int main() {
  long long int n{};
  cin >> n;
  long long int side = sqrt(n);
  long long int side2 = side;
  long long int ans = side * side2;
  if (ans == n)
    cout << side + side2 << endl;
  else if ((side + 1) * (side2) >= n)
    cout << side + side2 + 1 << endl;
  else if ((side + 1) * (side2 + 1) >= n)
    cout << side + side2 + 2 << endl;
  return 0;
}
