#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define ll long long
#define rep(i,n) for (int i = 0; i < (n); i++)
#define coutf(f) cout << fixed << setprecision(f)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()

int main() {
    ll n;
    cin >> n;
    ll left = 0, right = n + 1;
    while (right - left > 1) {
        ll mid = (left + right) / 2;
        ll d = n / mid;
        if (mid >= d) {
            right = mid;
        }
        else {
            left = mid;
        }
    }
    ll ans = right - 1 + n / right;
    cout << ans << endl;
    return 0;
}