Solution Review: Implementing the Fibonacci Series

def fib(n):
    # The first and second values will always be fixed
    first = 0
    second = 1
    if n < 1:
        return -1
    if n == 1:
        return first
    if n == 2:
        return second
    count = 3  # Starting from 3 because we already know the first two values
    while count <= n:
        fib_n = first + second
        first = second
        second = fib_n
        count += 1  # Increment count in each iteration
    return fib_n
n = 7
print(fib(n))