#include<bits/stdc++.h>
using namespace std;
#define ll  long long
#define pb  push_back
#define all(x) (x).begin(), (x).end()
#define  gcd(a,b)  __gcd(a,b)
#define    lcm(a,b)  (a*b)/__gcd(a,b)
#define optimize() ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);

void solve(){
    ll n; cin>>n;
    ll cnt=0;
    for(ll i=1; i*i<=n; i++){
        if(i*i<=n) cnt++;
        if((i)*(i+1)<=n) cnt++;
    }
    cout<<cnt;
}

signed main()
{
    optimize();
    ll t=1;
    //cin>>t;
    while(t--) solve();
    return 0;
}