def toStrDig(n, dig) :
    s = str(n)
    if len(s) < dig   :
        s = ('0' * (dig - len(s))) + s
    return s 
S = input().split()
x = (int(S[0])-9+24)%24 + int(S[1])/60
y = float(S[2][3 : ])
z = x + y
print(toStrDig((int(z)+24)%24, 2) + ":" +toStrDig(int((z - int(z)) * 60), 2))