(Python) 백준 10866 / 덱

import sys

deque = []
innn = [] # 몇개 들어올지 몰라 리스트로 받음

input = sys.stdin.readline

a = int(input())
for _ in range(a):
  innn = input().split()
  b = innn[0]
  if len(innn) == 2:
    c = innn[1]  
  if (b == "push_front"):
    deque.insert(0, c)
  elif (b == "push_back"):
    deque.append(c)
  elif (b == "pop_front"):
    if deque:
      print(deque[0])
      del deque[0]
    else:
      print(-1)
  elif (b == "pop_back"):
    if deque:
      print(deque[len(deque) - 1])
      del deque[len(deque) - 1]
    else:
      print(-1)
  elif (b == "size"):
    print(len(deque))
  elif (b == "empty"):
    if deque:
      print(0)
    else:
      print(1)
  elif (b == "front"):
    if deque:
      print(deque[0])
    else:
      print(-1)
  elif (b == "back"):
    if deque:
      print(deque[len(deque) - 1])
    else:
      print(-1)