def solution(book_time):
reg_time = []
for bt in book_time:
h, m = bt[0].split(':')
s = int(h)*60 + int(m)
h, m = bt[1].split(':')
e = int(h)*60 + int(m) + 10
reg_time.append([s, e])
# 완탐.
result = 0
for case in range(0, 24*60):
cnt = 0
for r_t in reg_time:
if r_t[0] <= case < r_t[1]:
cnt +=1
result = max(result, cnt)
return result