Błędna odpowiedź, pisane w python 3.7 wysyłane jako 3.5.
while True:
try:
phrase = input()
except EOFError:
break
phrase = list(phrase)
tab = []
while True:
if phrase[0] != " ":
tab.append(phrase[0])
del(phrase[0])
else:
del(phrase[0])
break
phrase.insert(0, tab[0])
del(tab[0])
j = 0
for i in range(len(phrase)):
if phrase[i] == " ":
phrase.insert(i+1, tab[j])
j+=1
print("".join(phrase))