class LexSort
{
static void solve(String s,String out, ArrayList<String> ans ,int i){
if(i==s.length()){
ans.add(out);
return;
}
char ch=s.charAt(i);
solve(s,out,ans,i+1);
solve(s,out+String.valueOf(ch),ans,i+1);
}
//Function to return the lexicographically sorted power-set of the string.
static ArrayList<String> powerSet(String s)
{
ArrayList<String> ans= new ArrayList<>();
solve(s,"",ans,0);
return ans;
}
}