#include <iostream>
#include <cstdio>
#include <string>
#include <algorithm>
#include <utility>
#include <cmath>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <tuple>
#include <numeric>
#include <functional>
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vector<ll>> vvl;
typedef pair<ll, ll> P;
#define rep(i, n) for(ll i = 0; i < n; i++)
#define exrep(i, a, b) for(ll i = a; i <= b; i++)
#define out(x) cout << x << endl
#define exout(x) printf("%.10f\n", x)
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define pb push_back
#define re0 return 0
const ll mod = 998244353;
const ll INF = 1e16;

ll floor_sqrt(ll x) {  // floor(√x) を誤差なく求める。計算量はO(log(x))。
    if(x < 0) {
        return -1;
    }
    if(x <= 1) {
        return x;
    }
    ll left = -1;
    ll right = x+1;
    while(right - left > 1) {
        ll mid = (left + right) / 2;
        if(mid <= x / mid) {
            left = mid;
        }
        else {
            right = mid;
        }
    }
    return left;
}

int main() {
    ll n;
    cin >> n;

    ll x = floor_sqrt(n);

    out(x + n / (x + 1));
    re0;
}