import sys
try:
    import os
    f = open('input.txt', 'r')
    sys.stdin = f
except FileNotFoundError:
    None
from math import sqrt, ceil,floor
from collections import deque, Counter, defaultdict
# defaultdict(int)
input=lambda: sys.stdin.readline().strip()
sys.setrecursionlimit(11451419)
from decimal import ROUND_HALF_UP,Decimal  #変換後の末尾桁を0や0.01で指定
  #Decimal((str(0.5)).quantize(Decimal('0'), rounding=ROUND_HALF_UP))
from functools import lru_cache
from bisect import bisect_left as bileft, bisect_right as biright
from fractions import Fraction as frac  #frac(a,b)で正確なa/b
# @lru_cache(maxsize=10**10)
#######ここまでテンプレ#######
#ソート、"a"+"b"、再帰ならPython3の方がいい
#######ここから天ぷら########

a,b,s = map(str ,input().split())
a=int(a);b=int(b)
sa = Decimal(s[3:])-Decimal("9")

# print(int(sa))

# print(sa)
if sa<0:
    if abs(sa%1) <0.01:
        a+= int(sa)
    else:
        a+= floor(sa)
        hun = 10-int(s[-1])
        # print(hun)
        b+= hun *6
else:
    a+=int(sa)
    b += (sa%1)*60
    b=int(b)

if b>=60:
    b-=60
    a+=1
a%=24

ji = "0"+str(a) if 0<=a<=9 else str(a)
hun = "0"+str(b) if 0<=b<=9 else str(b)
print(ji+":"+hun)