def minute_to_time(t:int):
    return "{:02}:{:02}".format(t // 60,t % 60)

def my_round(n:float):
    return round(n*2)//2

start = 10 * 60
distance = int(input())
minute = my_round(distance / 100 * 60)
print(minute_to_time(start + minute))