//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (ll)(n); i++)
#define all(a) (a).begin(), (a).end()
using ll = long long;
const int INF32 = 2e9;
const ll INF64 = 4e18;

int main() {
    ll N;
    cin >> N;
    ll cnt = 0;
    for(ll i = 1; i*i <= N; i++){
        cnt++;
    }
    cout << cnt << endl;
    return 0;
}