Prime numbers (sieve of Eratosthenes)

n = int(input())
prime = []
num = [1] * n
for i in range(4, n, 2):
    num[i] = 0
if n > 1:
    prime.append(2)
f = 1
l = 1
while f != 0:
    f = 0
    for i in range(l + 2, n, 2):
        if num[i] == 1:
            f = i
            break
    if f == 0:
        break
    l = f
    prime.append(f)
    for i in range(f + f, n, f):
        num[i] = 0
print(prime)