#include <bits/stdc++.h>
long long gcd(long long a, long long b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
long long lcm(long long a, long long b) { return (a * b) / gcd(a, b); }
const int MOD = 1e12 + 7;
const int MAX = 1e6 + 2;
const int INF = 0x3f3f3f3f;
using namespace std;
int main() {
  long long n, p = 0;
  cin >> n;
  p = sqrt(n);
  if (p * p >= n) {
    cout << p * 2;
  } else if (p * (p + 1) >= n) {
    cout << p * 2 + 1;
  } else {
    cout << p * 2 + 2 << endl;
  }
  return 0;
}
