#include <bits/stdc++.h>
using namespace std;
#define MOD 998244353
#define ll long long
#define ull unsigned long long
#define ld long double
const int MAX_n = 1e5 + 5;
#define MAX_X 1000000
const int InF = 1e9; // for int
const ll INF = 1e18; // for ll

void solve()
{
    int n;
    cin>>n;
    int tem=sqrt(n);
    if(tem*tem==n)
    cout<<(2*tem)-1<<endl;
    else
    cout<<2*tem<<endl;

    
}

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

    solve();
    return 0;
}