#include <iostream>
#include <cmath>
using namespace std;
int main()
{
double a, b, x, y;
cin >> a >> b >> x;
if (x > 2)
y = pow(a + b, 1 / 3) * pow(sin (x), 2);
else
y = log(abs(x / (a * b)));
cout<<"y="<<sin(y);
}
