# if n == 1, then move a to c directly
# if n > 1, then first consider how to move the first n-1 from a to b
# second is to move the last 1 from a to c
# The third also the last step is to move n-1 from b to c
def move(n,a,b,c):
if n == 1:
print(a,'-->',c)
else:
move(n-1,a,c,b)
move(1,a,b,c)
move(n-1,b,a,c)
H