//с++
#include <iostream>
#include <cmath>
signed main() {
double x, y;
std::cin >> x;
y = (2 - x) / (3 * exp(abs(x) - 1)) - sqrt(4 + pow(x, 2) / 2.4);
std::cout << y;
return 0;
}
//с++
#include <iostream>
#include <cmath>
signed main() {
double x, y;
std::cin >> x;
y = (2 - x) / (3 * exp(abs(x) - 1)) - sqrt(4 + pow(x, 2) / 2.4);
std::cout << y;
return 0;
}