import sys

tmp_s = "abcdefghijklm"
dic = {}

for i in tmp_s:
    dic[i] = 0

s = raw_input()

for i in s:
    if dic[i] == 3 or i not in tmp_s:
        print "Impossible"
        sys.exit()
    else:
        dic[i] += 1

n2 = [0, []]
n1 = [0, []]
n0 = [0, []]

keys = dic.keys()


for i in keys:
    if dic[i] == 2:
        n2[0] += 1
        n2[1].append(i)
    elif dic[i] == 1:
        n1[0] += 1
        n1[1].append(i)
    else:
        n0[0] += 1
        n0[1].append(i)

if n2[0] == 1 and n0[0] == 1:
    print n0[1][0]
elif n0[0] == 1 and n2[0] == 0:
    print n2[1][0]
elif n0[0] == 0 and n2[0] == 0:
    x = sorted(n1[1])
    print x
    for i in x:
        print i