l = [0] * n
for i in range(1, n + 1):
if not l[i - 1]:
coprimes = []
for j in range(2, i):
if gcd(i, j) == 1:
coprimes.append(j)
l[i - 1] = 1 + len(coprimes)
for c in coprimes:
if i * c > n:
break
l[(i * c) - 1] = l[i - 1] * l[c - 1]
return l
s = Sieve(10 ** 7)
ps = s.list()
def phi(n):
if n < 2:
return 1
if s.is_prime(n):
return n - 1
if (n & 1) == 0:
m = n >> 1
return phi(m) if m & 1 else phi(m) << 1
for p in ps:
if p > n:
break
