def read_node(it):
    child_count, meta_count = next(it), next(it)

    child_sum = sum(read_node(it) for _ in range(child_count))
    own_sum = sum(next(it) for _ in range(meta_count))
    return child_sum + own_sum


it = (int(x) for x in input().split())
print(read_node(it))