A51 - Stack
https://atcoder.jp/contests/tessoku-book/tasks/tessoku_book_ay
提出
code: python
q = int(input())
queries = list(input().split()) for _ in range(q)
stack = []
for query in queries:
if query0 == "1":
stack.append(query1)
elif query0 == "2":
print(stack-1)
else:
stack.pop()