program to get as output the serie 0, 1, 1, 2, 3. 5, 8. 13, 21

def fibonacci(n):
    if n < 0:
        print("Incorrect input")
    # First Fibonacci number is 0
    elif n == 0:
        return 0
    # Second Fibonacci number is 1
    elif n == 1:
        return 1
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)
 
# Driver Program
 
print(fibonacci(9))