#include <iostream>

using namespace std;

double F(double x) {
    return x*x*x + 5*x - 3;
    // return x*x*x - 8;
    // return x*x - 4;
}

float input (string msg) {
    cout << msg;
    float x;
    cin >> x;
    return x;
}

int main()
{
    float p = -2,
          q = 2,
          E1 = 0.0001,
          s;

    p = input("Podaj p: ");
    q = input("Podaj q: ");
    E1 = input("Podaj E1: ");

    s = (p + q) / 2;

    while (F(p) != 0 && F(q) != 0 && q - p >= E1) {
        s = (p + q) / 2;
        if (F(p) * F(s) > 0) {
            p = s;
        } else {
            q = s;
        }
    }

    if (F(p) == 0) {
        cout << p << endl;
        return 0;
    } else if (F(q) == 0) {
        cout << q << endl;
        return 0;
    }

    cout << "Wynik: " << s << endl;
    return 0;
}