nothing eternal world Kostya understand 7th January see partially dead fourcolor garlandnow goal replace dead light bulb do not know light bulbs color require it guarantee color light workingIt know garland contain light bulbs color red blue yellow green the garland follow consecutive light bulb light bulbs color for example garland look like RYBGRYBGRY YBGRYBGRYBG BGRYB look like BGRYG ybgrybygr BGYBGY Letters denote color r red B blue Y yellow G greenuse information color light bulb work count number dead light bulb color