#include <iostream>
using namespace std;

int main() {
    long long n;
    cin >> n;
    long long count = 0;

    for (long long a = 1; ; a++) {
        long long x1 = a * a;
        long long x2 = a * (a + 1);

        if (x1 <= n) count++;
        if (x2 <= n) count++;

        // If both are greater than n, no further balanced numbers are possible
        if (x1 > n && x2 > n) break;
    }

    cout << count << endl;
    return 0;
}