#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  if (n <= 3) {
    cout << n + 1 << endl;
    return 0;
  }
  int x = sqrt(n);
  if (x * x == n) {
    cout << 2 * x << endl;
  } else if (n > x * x and n <= (x + 1) * x) {
    cout << (2 * x) + 1 << endl;
  } else if (n > (x + 1) * x and n < (x + 1) * (x + 1)) {
    cout << (2 * x) + 2 << endl;
  }
  return 0;
}
