def main():
    import sys
    input = sys.stdin.read
    data = input().split()
    
    N = int(data[0])
    K = int(data[1])
    A = list(map(int, data[2:2 + N]))
    
    total = sum(A)
    low = 0
    high = total
    
    def is_possible(M):
        current_sum = 0
        count = 0
        for num in A:
            current_sum += num
            if current_sum >= M:
                count += 1
                current_sum = 0
                if count == K:
                    return True
        return count == K and current_sum >= M
    
    while low < high:
        mid = (low + high + 1) // 2
        if is_possible(mid):
            low = mid
        else:
            high = mid - 1
    print(low)

if __name__ == "__main__":
    main()