02. Trains

# 2SPORED MEN
# train_length = int(input())
# train = [0] * train_length
# command = input()
# while command != 'End':
#     tokens = command.split(" ")
#     key_word = tokens[0]
#     if key_word == 'add':
#         people = int(tokens[1])
#         del train[-1]
#         train.append(people)
#     if key_word == 'insert':
#         del train[0]
#         index = int(tokens[1])
#         people = int(tokens[2])
#         train.insert(index, people)
#         # print(train)
#     if key_word == 'leave':
#         index = int(tokens[1])
#         people = int(tokens[2])
#         leave = train[index] - people
#         train.pop(index)
#         train.insert(index, leave)
#     command = input()
# print(train)