#pragma GCC optimize("Ofast")
#include <iostream>
#include <math.h>
#include <cstdint>
using namespace std;
#ifndef ONLINE_JUDGE
#define debug(x) cerr << #x << " = " << x << endl
#else
#define debug(x)
#endif

using ll = long long;

void Solve()
{
    int n;
    cin >> n;
    int c = ceil(sqrt(n));
    int f = floor(sqrt(n));
    if(c == f) cout << c + f - 1 << endl;
    else cout << f + f << endl;
}

int32_t main()
{
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    ll t = 1;
    // cin >> t;
    while (t--)
        Solve();
    return 0;
}