#include <bits/stdc++.h>
using namespace std;
bool IsPowerOfTwo(long long x) { return (x != 0) && ((x & (x - 1)) == 0); }
bool isPerfectSquare(long double x) {
  long double sr = sqrt(x);
  return ((sr - floor(sr)) == 0);
}
int main() {
  int n;
  cin >> n;
  int ans = n + 1;
  for (int i = 1; i * i <= n; i++) {
    ans = min(ans, n / i + (bool)(n % i) + i);
  }
  cout << ans;
}
