def main(n):
"""Return the sum of all the primes below n"""
i = 3
s = 2
while i<n:
if is_prime(i):
s += i
i += 2
return s
def find_primes(n):
'''
Find the nth first prime numbers
'''
primes = [2]
i = 3
while len(primes)<n:
if is_prime(i):
primes.append(i)
i += 2
return primes