#include <iostream>
#include <cmath>

#ifndef M_PI
#define M_PI 3.14
#endif

int main(void){
	using namespace std;

	int n;
	cin >> n;
	
	cout << static_cast<int>(sqrt(n / M_PI)) << endl;

	return 0;
}

// n = r * r * pi
// r = sqrt(n / pi)