s=gets
a=(?a..?m).map{|c| s.count(c)}

res=[]
(?a..?m).each_with_index do |c, i|
    a[i]+=1
    two=(0..12).count{|x|a[x]==2}
    one=(0..12).count{|x|a[x]==1}
    res<<c if two==1 and one==12
    a[i]-=1
end
if res[0]
    puts res
else
    puts "Impossible"
end