#include <bits/stdc++.h>

using namespace std;

int main() {
    int n;
    cin >> n;
    int cnt = 1;
    for (int i = 2; i <= n; i++)
    {
        int x = sqrt(i);
        if (x * x == i || x * (x + 1) == i) cnt++;
    }
    cout << cnt;

}