#include <iostream>
using namespace std;

int main() {
	int k;
	double n, a, m, i, b;
	cin >> k;
	n = 0;
	m = 1.0;
	i = 1.0;
	a = 0;
	do {
		a = m / i;
		n = n + a;
		i += 1;
	} while (n <= k);
	b = i - 1.0;
	cout << b << endl;
	return 0;
}