class Solution:
    def arrangeCoins(self, n: int) -> int:
        ans = 0
        b, e = 0, int((n * 2) ** 0.5) + 5
        while b < e:
            m = (b + e) // 2
            coins_used = (m * (m + 1)) // 2
            if coins_used <= n:
                ans = m
                b = m + 1
            else:
                e = m
        return ans