题解 | #小乐乐定闹钟#

start,keep=input().split(' ')        # 输入开始时间和持续时间
keep=int(keep)
hour,minute=map(int,start.split(':'))    # hour开始时间的小时，minute开始时间的分钟数
# print(hour,minute,keep)
# newminute
if  minute+keep<60:
    newminute=(minute+keep)%60        # newminute
elif minute+keep>60:
    newminute=(minute+keep)%60        # minute进位
    newhour=hour+((minute+keep)//60)    # 增加了多少hours
if newhour>23:                        # newhour大于等于24的情况
    newhour=newhour%24                

print('{:02d}:{:02d}'.format(newhour,newminute))