program hanoi
　implicit none
　integer :: i
　read *, i
　if (i>0) call solve(i, 1, 3, 2)
contains
　recursive subroutine solve(n, from, to, tmp)
　　integer, intent(in) :: n, from, to, tmp
　　if (n>0) then
　　　call solve(n-1, from, tmp, to)
　　　print *, "Move disk #", n, " from", from, " to", to
　　　call solve(n-1, tmp, to, from)
　　end if
　end subroutine solve
end program hanoi