a = []
isTwenty = True
for i in range(12):
if isTwenty:
a.append(20)
isTwenty = False
else:
a.append(10)
print(a)
a = []
isTwenty = True
for i in range(12):
if isTwenty:
a.append(20)
isTwenty = False
else:
a.append(10)
isTwenty = True
print(a)