# Leetcode 441 - Arranging coins

`Note:`

- Use math
`(root = sqrt(8n - 1) - 1 ) / 2`

.

`Question:`

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 |

`Code:`

1 | /** |