time = input()

h, m = time.split(":")
h, m = int(h), int(m)
rh = int(h % 10 * 10 + h // 10)
rm = int(m % 10 * 10 + m // 10)

if 6 <= h <= 9:
    print("10:01")
elif 16 <= h <= 19:
    print("20:02")
else:
    if rh >= m:
        print(f"{'' if h >= 10 else '0'}{h}:{'' if rh + 1 > 10 else '0'}{rh}")
    elif rh + 10 < 60:
        if h + 1 < 24:
            print(f"{'' if h + 1 >= 10 else '0'}{h + 1}:{rh + 10}")
        else:
            print("00:00")
    else:
        print("20:02")