๋น„ํŠธ 2ํผ ๋น ์งˆ๋•Œ 20%~40%์šด์ง€ํ•˜๋Š” ์•ŒํŠธ๋ณด์ง€๋ง๊ณ  ๋น„ํŠธ๋งŒ ๋ด๋ผ