Извиняюсь за возможную костыльность, но в целом код работатет.

one = input('Введите первую строку: ')

two = input('Введите вторую строку: ')

three = input('Введите третью строку: ')

l1 = len(one)

l2 = len(two)

l3 = len(three)

if l1 > l2 and l1 > l3 and l2 > l3:

print(three, two, one)

elif l1 < l2 and l1 > l3 and l2 > l3:

print(three, one, two)

elif l1 < l2 and l1 < l3 and l2 > l3:

print(two, three, one)

elif l1 < l2 and l1 < l3 and l2 < l3:

print(three, two, one)

elif l1 > l2 and l1 > l3 and l2 < l3:

print(two, three, one)

elif l1 > l2 and l1 < l3 and l2 < l3:

print(two, one, three)