#include
#include
int main()
{
#define _USE_MATH_DEFINES
float k, a, n;
std::cin >> k >> a >> n;
float
y = (k + M_PI / 4) * (a - 5 * M_PI),
x = M_PI / 7 * k - n * (M_PI - 1);
std::cout << "F = " << (1 - std::tan(x)) * (1 + std::sin(2 * y)) << std::endl;</p>
return 0;
}
