N,M = map(int,input().split())
A = list(map(int,input().split()))
suma = sum(A)
lb = 0
ub = suma // M + 1

def check(x):
    tmp = 0
    mx = M * x
    for i in range(N):
        tmp += A[i] - mx
        if tmp < 0:
            return False
    return True

while ub - lb > 1:
    mid = (ub + lb) // 2
    if check(mid):
        lb = mid
    else:
        ub = mid
print(lb)