TypeError: 'int' object is not iterable Fabionacci function

am trying to make my own function of fibonacci, however, I keep getting the error in the title, why an integer is not iterable, and how can I make this function work? any alternative solution? it seems that I always have problems with lists being strictly string. I tried converting it to an integer by using

a = int(list(n))

but I still get the same error...

num = 10
def fibonacci(n):
    #complete the recursive function
    for i in range(n):
        counter = 0
        counter2 = -1
        a = list(n)
        if counter2 == -1:
            print(a[counter])
            counter += 1
            counter2 += 1
        else:
            print(a[counter] + a[counter2])
            counter += 1
            counter2 += 1

fibonacci(num)