Why am I receiving a SyntaxError: invalid syntax regarding the use of an elif function?

I am trying write a code which generates a series of responses: if the user enters 1 number, several numbers or a string instead in order to generate a list of Fibonacci numbers. The code is as follows:

def fib (a, b):
    return a + b

number = int(input("Please write how many Fibonacci numbers you wish to have generated: "))

fibonacci_list = []
for n in range(number):
    if n in [0, 1]:
        fibonacci_list += [1]
        print("The first", number, "Fibonacci number is:", fibonacci_list)
    elif:
        fibonacci_list += [fib(fibonacci_list[n-2], fibonacci_list[n-1])]
        print("The first", number, "Fibonacci numbers are:", fibonacci_list)
    else:
        print('Sorry could not recognise the input')