from collections import defaultdict
s = input()
se = set(s)

d = defaultdict(int)
for c in list(s):
    d[c]=d[c]+1
print(d)
num2 = len(list(filter(lambda x :x==2,d.values())))
if num2==6 and len(se)==7 and len(s)==13:
    for k,v in d.items():
        if v==1:
            print(k)
else:
    print("Impossible")