program water_bottle
  implicit none
  real(8), parameter :: pi = 3.14159265358979d0, rad2deg = 180.d0/pi
  integer :: a, b, x
  real(8) :: theta
  character(64) :: ans
  read(*,*) a, b, x
  if (a*a*b > 2*x) then
    theta = atan2(real(2*x,8),real(a*b*b,8))
  else if (a*a*b < 2*x) then
    theta = atan2(real(a*a*a,8),2.d0*real(a*a*b-x,8))
  else
    theta = atan2(real(b,8),real(a,8))
  end if
  write(ans,'(f32.16)') (0.5d0*pi-theta)*rad2deg
  write(*,'(a)') trim(adjustl(ans))
end program water_bottle