#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;

int main()
{
	ll n; cin>>n;
	ll l=0, r=1e9+7;
	while(r-l>1){
		ll m=(l+r)/2;
		if(m*m<=n) l=m;
		else r=m;
	}
	cout<<l+n/(l+1)<<endl;
	return 0;
}