# infinite generator
def fib():
    a, b = 0, 1
    while True:
        yield a 
        a, b = b, a + b 

# generate first 5 fib numbers
fibs = fib()
f = [next(fibs) for _ in range(5)]
print('first 5:', f) 

# generate next 5 fib numbers
f = [next(fibs) for _ in range(5)]
print('next 5 :', f)

# find the nth fib number, v1
nth_fib = fib()
n = 10
for i in range(n): f = next(nth_fib)
print(f'fib({n}): {f}')

# find the nth fib number, v2
nth_fib = fib()
n = 10
f = [next(nth_fib) for _ in range(n)][-1]
print(f'fib({n}): {f}')