from collections import deque
d = deque()
N = int(input()) #number of operations
for i in range(N):
    oper = list(input().split())   
    if oper[0] == 'append':
        d.append(int(oper[1]))
    elif oper[0] == 'appendleft':
        d.appendleft(int(oper[1]))
    elif oper[0] == 'pop':
        d.pop()
    elif oper[0] == 'popleft':
        d.popleft()
    else:
        print()
print(*d)``