def main():
    import sys
    input = sys.stdin.read().split()
    N = int(input[0])
    K = int(input[1])
    A = list(map(int, input[2:2+N]))
    
    total = sum(A)
    
    if K > N:
        print(0)
        return
    
    if K == 0:
        print(0)
        return
    
    left = 1
    right = total // K
    ans = 0
    
    def can_achieve(M):
        if M == 0:
            return True
        count = 0
        current = 0
        for num in A:
            current += num
            if current >= M:
                count += 1
                current = 0
                if count >= K:
                    return True
        return False
    
    while left <= right:
        mid = (left + right) // 2
        max_a = max(A)
        if max_a < mid:
            right = mid - 1
            continue
        if total < K * mid:
            right = mid - 1
            continue
        if can_achieve(mid):
            ans = mid
            left = mid + 1
        else:
            right = mid - 1
    
    print(ans)

if __name__ == "__main__":
    main()