#include <iostream>
#include <math.h>
using namespace std;
int main() {
    double alpha;
    double x, y, z; cin >> x >> y >> z;
    if (y <= 0)
    {
        cout << "undefined, try again";
        return 0;
    }
    alpha = log(pow(y, -sqrt(abs(x)))) * (x - y / 2) + pow(sin(atan(z)), 2);
    cout << "alpha = " << alpha;
    return 0;
}