/* -*- coding: utf-8 -*-
 *
 * 1162.cc:  No.1162 Many Quotients hard - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

typedef long long ll;

/* global variables */

/* subroutines */

/* main */

int main() {
  ll n;
  scanf("%lld", &n);

  ll a = sqrtl(n);
  //printf("a=%lld\n", a);

  if (n / (a + 1) != n / (a + 2)) a++;
  printf("%lld\n", a + n / (a + 1));
  //printf("a=%lld\n", a);
  return 0;
}