for _ in range(int(input())):
    n = int(input())
    arr = list(map(int, input().split()))

    count = 0

    new_arr = []
    for i in arr:
        if i % 3 == 0:
            count += 1
        else:
            new_arr.append(i)
    new_sum = sum(new_arr)

    if new_sum % 3 == 0:
        count += len(new_arr)
    elif new_sum % 3 == 1:
        if 1 in new_arr:
            count += (len(new_arr) - 1)
    elif new_sum % 3 == 2:
        if 2 in new_arr:
            count += (len(new_arr) - 1)
        elif new_arr.count(1) >= 2:
            count += (len(new_arr) - 2)

    print(count)