import sys

def main():
    N, K = map(int, sys.stdin.readline().split())
    A = list(map(int, sys.stdin.readline().split()))
    
    if K == 0:
        print(0)
        return
    
    if K >= N:
        print(min(A))
        return
    
    def is_possible(mid):
        count = 0
        current_sum = 0
        for num in A:
            current_sum += num
            if current_sum >= mid:
                count += 1
                current_sum = 0
                if count >= K:
                    return True
        return False
    
    low = 1
    high = sum(A)
    ans = 0
    
    while low <= high:
        mid = (low + high) // 2
        if is_possible(mid):
            ans = mid
            low = mid + 1
        else:
            high = mid - 1
    
    print(ans)

if __name__ == "__main__":
    main()