from itertools import accumulate


def main():
    n, m = map(int, input().split())
    a = [0] + list(map(int, input().split()))
    acc = list(accumulate(a))
    
    def isok(k):
        return all(acc[i] >= m * k * i for i in range(1, n))

    left = 0
    right = 10 ** 9 + 1
    while right - left > 1:
        mid = (left + right) // 2
        if isok(mid):
            left = mid
        else:
            right = mid
    print(left)


if __name__ == "__main__":
    main()