Fibonacci implementation (python) - Can you find a more efficient way?

f.py

#Using a loop:
def f(n):
        	
	if n == 1 or n == 0 : return n
	
	else:
		x = 0
		y = 1
		r = 0
		for i in range(n - 1):
			r = x + y
			x = y
			y = r

	return r

n = input("Enter an integer to calculate fibonacci sequence:")
print(f(n))

#Using recursion:
def f(n):
	
	if n == 1 or n == 0 : return n

	else:
		return f(n-1) + f(n-2)

n = input("Enter a number, bitch:")
print(f(n))