#include <bits/stdc++.h>
using namespace std;


#define int long long

void iusearchbtw () {
        int n; cin >> n;
        int x = sqrt(n);
        int ans = 2 * x;
        if (x * (x + 1) > n) ans--;
        cout << ans << endl;
}






signed main () {
        ios_base::sync_with_stdio(0);
        cin.tie(0);
        cout.tie(0);
        int tt = 1;	
        //cin >> tt;
	while (tt --> 0) iusearchbtw();
}