#include <bits/stdc++.h>
using namespace std;
long long p1 = 1000000007;
long long mod = 998244353;
long long power(long long x, long long y) {
  long long ans = 1;
  x = x % p1;
  while (y > 0) {
    if (y & 1) ans = (ans * x) % p1;
    y = y >> 1;
    x = (x * x) % p1;
  }
  return ans;
}
int main() {
  long long n;
  cin >> n;
  long long k = floor(sqrt(n));
  long long ans = 2 * k;
  long long rem = n - k * k;
  ans += rem / k;
  if (rem % k != 0) ans++;
  cout << ans;
  return 0;
}
