풀이 import sys N=int(sys.stdin.readline()) deque=[] for i in range(N): words=sys.stdin.readline().split() if words[0]=='push_front': deque.insert(0,words[1]) elif words[0]=='push_back': deque.append(words[1]) elif words[0]=='pop_front': if deque: print(deque.pop(0)) else: print(-1) elif words[0]=='pop_back': if deque: print(deque.pop()) else: print(-1) elif words[0]=='size': print(len(deque)) eli..