You have n coins and you want to build a staircase with these coins. The staircase consists of k rows where the ith row has exactly i coins. The last row of the staircase may be incomplete.

Given the integer n, return the number of complete rows of the staircase you will build.

  Example 1:

Input: n = 5 Output: 2 Explanation: Because the 3rd row is incomplete, we return 2.

Example 2:

Input: n = 8 Output: 3 Explanation: Because the 4th row is incomplete, we return 3.

  Constraints:

1 <= n <= 2³¹ - 1