#include <bits/stdc++.h>
#define rep(i,n) for(int i=(0);i<(n);i++)

using namespace std;

typedef long long ll;
typedef pair<ll, ll> pll;

template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }

ll n;
bool cond(ll x){
	return x * x > n;
}

// condを満たす最小のxを求める(lower_bound)
// 全てのxが条件を満たさない場合はnを返す(nはとりえない値)
ll lower_bound_cond(){
	ll lb = -1, ub = n;

	while(ub - lb > 1){
		ll mid = (lb + ub) / 2;

		if(cond(mid)) ub = mid;   // Answer is in (lb, mid]
		else lb = mid;            // Answer is in (mid, ub]
	}

	// now lb + 1 = ub
	return ub;
}



int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);

	cin >> n;

	if(n <= 10){
		set<ll> st;
		for(ll i = 1; i <= n; i++) st.insert(n / i);
		cout << st.size() << endl;
		exit(0);
	}

	ll x = lower_bound_cond();
	cout << x + n / x - 1 << endl;
}