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)
    low = 1
    high = total // K
    answer = 0
    
    while low <= high:
        mid = (low + high) // 2
        count = 0
        current = 0
        for num in A:
            current += num
            if current >= mid:
                count += 1
                current = 0
                if count >= K:
                    break
        if count >= K:
            answer = mid
            low = mid + 1
        else:
            high = mid - 1
    print(answer)
    
if __name__ == "__main__":
    main()