def solution(record):
answer = []
ids = {}
for r in record:
line = r.split()
if line[0] == 'Change' or line[0] == 'Enter':
ids[line[1]] = line[2]
for r in record:
line = r.split()
if line[0] == 'Enter':
answer.append(f"{ids[line[1]]}님이 들어왔습니다.")
if line[0] == 'Leave':
answer.append(f"{ids[line[1]]}님이 나갔습니다.")
return answer