T = input()
hh = int(T[0]+T[1])
mm = int(T[3]+T[4])
if mm < 55 and mm > 5:
    M = mm + 5
elif mm >= 0 and mm <= 5 :
    M = str(0)+str(mm+5)
else :
    M = str(0)+str(mm + 5 - 60)
    hh += 1
if hh == 24 :
    H = str(0)+str(0)
elif hh >= 10 :
    H = hh
else :
    H = str(0)+str(hh)
print("{}:{}".format(H,M))