from random import randint, seed

seed(0)

a = ['000000000000'] + [str(randint(100000000000,999999999999)) for _ in xrange(200000)]
print 'generate 200000 a'

b = [str(randint(100000000000,999999999999)) for _ in xrange(200000)] + ['000000000000']
print 'generate 200000 b'

a = set(a)
b = set(b)

print 'convert to set'

print a & b