u=['99', 'f0', '11', '31', '3f', 'f6', '9d', '52']
v=['89', 'fa', '1f', '34', '38', 'eb', '8c', '59']



u = [int(x,16) for x in u]
v = [int(x,16) for x in v]

xx = [u[i]^v[i] for i in range(len(u))]

dd = open('/usr/share/dict/words','r').readlines()

dd = [w.rstrip().lower() for w in dd]
dd8=[map(ord,w) for w in dd if len(w)==8]

def f(w):
    return [w[i]^xx[i] for i in range(8)]

res = [w for w in dd8 if f(w) in dd8]

print len(res)
print ''.join(map(chr,res[0]))
print ''.join(map(chr,res[1]))


## 2
## computer
## security