题解 | #小乐乐定闹钟#

time, interval = input().split()
idx = time.index(":")

time_h = int(time[:idx])
time_m = int(time[idx+1:])

#注意下面的切片是错误的，start_pos 不能等于stop_pos
#切片区间左闭右开
# time_h = int(time[:idx-1])
# time_m = int(time[idx+1:-1])


# print(type(time))
# print(time)
# print(idx)
# print(interval)

time_m = time_m+int(interval)%60
time_h += int(interval)//60 + time_m // 60
time_h = time_h%24
time_m = time_m%60

print("%02d:%02d" %(time_h, time_m))