def solution(s):
answer = []
s = s.split('},{')
s[0] = s[0].replace('{','')
s[-1] = s[-1].replace('}','')
#print(s)
s.sort(key=len)
for i in s:
i = i.split(',')
for j in i:
if int(j) not in answer:
answer.append(int(j))
#print(answer)
return answer
solution("{{2},{2,1},{2,1,3},{2,1,3,4}}")
