#def fac(N):
#    if N <= 1:
#        return 1
#    else:
#        return N * fac(N-1)

# Function to model factorial function using recursion
def fac(N):
    if N <= 1:
        return 1
    return N * fac(N-1)

# Function to model the Fibonnaci Series using recursion
def fibo(n):
    if n == 1 or n == 2:
        return 1
    return fibo(n-1) + fibo(n-2)

# Function to model the mathemtical linear series: a(n+1) = a(n) + 5 where a(0) = 3
def f(n):
    # base case:
    if n == 0:
        return 5
    return f(n-1)+3