Число Фибоначчи с номером n

def fib(n):
    c,p=0,1
    for i in range(1,n+1):
        c,p=c+p,c
    return c

for _ in range(n):

def phib(n):
    if n == 1 or n == 2:
        return 1
    return phib(n - 1) + phib(n - 2)
n = int(input())
print(phib(n))

def fib(n):
    c,p=0,1
    for i in range(1,n):
        c,p=c+p,c
    return c

def fib(n):
    c,p=0,1
    for i in range(n):
        c,p=c+p,c
    return c

def fib(n):  # формула Бине
    a = (1 + 5**0.5)/2
    return int((a**n - (-a)**-n) / (2*a - 1))
 
for i in range(100):
    print(i, fib(i))

n = int(input('n: '))
prev = 1
curr = 0
count = 1
while count < n:
    curr, prev = curr + prev, curr
    count += 1
print(curr)

n = int(input("n:"))
if n == 0:
    fibonacci_number = 0
elif n == 1:
    fibonacci_number = 1
elif n == 2:
    fibonacci_number = 1
else:
    previous_previous_number = 0
    previous_number = 1
    fibonacci_number = 1
    current_position = 3
    while current_position < n:
        fibonacci_number += previous_number
        previous_previous_number = previous_number
        previous_number = fibonacci_number - previous_previous_number
        current_position += 1
print(fibonacci_number)