3.6

#Python 3.5
#lhvu
#3.6

#- input: names = "cho meo ga chuot vit ngan"
#- output: ['m', 'e', 'u', 'v', 'i']

names =  "cho meo ga chuot vit ngan"
lista = []

for i in list(names):
    if names.count(i) == 1:
        lista.append(i)
print(lista)