from itertools import combinations
def solve(s):
    n = len(s)
    combs = []
    for i in range (1, n+1):
        # find all combinations of size 'i' from 's'
        temp = combinations(s, i)    
        # add those combinations to the list 'combs'
        combs += [''.join(e) for e in temp]
    combs.sort()
    return combs