def solution(A, K, L):
    # write your code in Python 3.6
    l = len(A)
    if K + L > l:
        return -1

    # i is the start of K
    # j is the start of L
    result = -1
    for i in range(l):
        for j in range(l):
            # K is the first interval
            if not ((i + K > l) or (j + L > l) or (i + K + 1 > j)):
                result = max(sum(A[i:i+K]) + sum(A[j:j+L])
                    , result)

            # L is the first interval
            if not ((i + K > l) or (j + L > l) or (j + L + 1 > i)):
                result = max(sum(A[i:i+K]) + sum(A[j:j+L])
                    , result)
    return result