program main
implicit none
integer :: i , j 
integer :: a( 5 ), k

do i = 1, 5
read(*,*) a(i)
end do
read(*,*) k

do i = 1, 5
   do j = i, 5
      if( a(j) - a(i) > k ) then
         write(*,*) ':('
         stop
      end if
   end do
end do
write(*,*) 'Yay!'


end program main
