#include <iostream>
#include <cmath>
#include <cstdlib>
#include <iomanip>

using namespace std;

typedef long double real;

struct complex {
    real re, im;
    
    complex(real r = 0, real i = 0) : re(r), im(i) {
    }
    
    complex(const complex &z) {
	re = z.re;
	im = z.im;
    }
    
    complex& operator= (const complex &z) {
	re = z.re;
	im = z.im;
    }
    
    bool operator== (const complex &z) const {
	return re == z.re && im == z.im;
    }
    
    bool operator!= (const complex &z) const {
	return re != z.re || im != z.im;
    }
    
    complex& operator+= (const complex &z) {
	re += z.re;
	im += z.im;
    }
    
    complex operator+ (const complex &z) const {
	complex result(*this);
	
	return result += z;
    }
    
    complex operator+() const {
	return *this;
    }
    
    complex& operator-= (const complex &z) {
	re -= z.re;
	im -= z.im;
    }
    
    complex operator- (const complex &z) const {
	complex result(*this);
	
	return result -= z;
    }
    
    complex operator-() const {
	return complex(-re, -im);
    }
    
    complex operator* (const complex &z) const {
	return complex(re*z.re - im*z.im, re*z.im + im*z.re);
    }
    
    complex& operator*= (const complex &z) {
	return *this = *this*z;
    }
    
    complex operator/ (const complex &z) const {
	real t = 1/(z.re*z.re + z.im*z.im);
	
	return complex((re*z.re + im*z.im)*t, (im*z.re - re*z.im)*t);
    }
    
    complex& operator/= (const complex &z) {
	return *this = *this/z;
    }
    
    real modulus2() const {
	return re*re + im*im;
    }
    
    real modulus() const {
	return sqrt(modulus2());
    }
};

int main() {
    real e = 1e-5;
    complex z(-0.75, e), c(z);
    int n = 0;
    
    while (true) {
	complex z1;
	z1 = z*z + c;
	
	if (z1.re*z1.re + z.im*z.im >= 4) {
	    break;
	}
	
	z = z1;
	++n;
    }
    
    cout << setprecision(20) << n*e << endl;
    
    return EXIT_SUCCESS;
}