You have 2020 piles of coins in front Of you. The first pile contains 1 coin, the second pile contains 2 coins, the third pile contains 3 coins and so on. So, the 2020th pile contains 2020 coins. Guess a positive integer k, in which piles contain at least k coins, take away exact k coins from these piles. Find the minimum number of turns you need to take way all of these coins?