#You are given a positive integer N which represents the number of steps in a staircase. You can either climb 1 or 2 steps at a time.
#Write a function that returns the number of unique ways to climb the stairs.
def staircase(n):
    if(n < 0):
        return 0 #illegal move
    if(n == 1):
        return 1 #just 1 step
    if(n == 2):
        return 2 # 1 step then 1 step, or 2 step
    return staircase(n-1) + staircase(n-2)
  
print(staircase(4))
# 5
print(staircase(5))
# 8
