for _ in range(int(input())):
    n = int(input())
    arr = list(map(int, input().split()))
    count = 0
    for i in arr:
        if i%3 == 0:
            count += 1
            arr.remove(i)
    if sum(arr)%3 == 0:
        count += len(arr)
    elif sum(arr)%3 == 1:
        if 1 in arr:
            count += (len(arr)-1)
    elif sum(arr)%3==2:
        if  2 in arr:
            count += (len(arr)-1)
        elif arr.count(1)==2:
            count += (len(arr)-2)
    print(count)