#include <bits/stdc++.h>
using namespace std;
long long factorial(long long n) {
  if (n == 0) {
    return 1;
  }
  return (n * factorial(n - 1)) % 998244353;
}
long long power(long long x, long long y) {
  long long out = 1;
  while (y > 0) {
    if (y & 1) out = (out * x) % 998244353;
    y = y >> 1;
    x = (x * x) % 998244353;
  }
  return out;
}
int main() {
  long long n, i;
  cin >> n;
  vector<long long> v1;
  long long temp;
  for (i = 0; i < 100000; i++) {
    v1.push_back((i * i));
  }
  for (i = 0; i < v1.size(); i++) {
    if (v1[i] > n) {
      temp = i - 1;
      break;
    }
  }
  long long ans;
  if ((temp * temp) >= n) {
    ans = 2 * temp;
  } else if (temp * (temp + 1) >= n) {
    ans = 2 * temp + 1;
  } else if ((temp + 1) * (temp + 1) >= n) {
    ans = 2 * temp + 2;
  }
  cout << ans << "\n";
}
