#include <bits/stdc++.h>
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int sqroot(int x) {
  int lo = 0, hi = x;
  while (lo < hi) {
    long long mid = (lo + hi + 1) / 2;
    if (mid * mid <= x) {
      lo = mid;
    } else {
      hi = mid - 1;
    }
  }
  return lo;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  if (n == 1) {
    cout << 2 << '\n';
    return 0;
  } else if (n == 2) {
    cout << 3 << '\n';
    return 0;
  }
  int sqr = sqroot(n);
  cout << 2 * sqr + (sqr * sqr != n) + (n - sqr * sqr > sqr) << '\n';
  return 0;
}
