def max_elements_divisible_by_3(arr):

    n = len(arr)
    dp = [[0] * 3 for _ in range(n)]
    dp[0][0] = 1 if arr[0] % 3 == 0 else 0
    dp[0][1] = 1 if arr[0] % 3 == 1 else 0
    dp[0][2] = 1 if arr[0] % 3 == 2 else 0
    for i in range(1, n):
        for j in range(3):
            r = (j + arr[i]) % 3
            dp[i][r] = max(dp[i - 1][r], dp[i - 1][j] + 1)
    return dp[n - 1][0]
def solve():
    n = int(input())
    arr = list(map(int, input().split()))
    ans = max_elements_divisible_by_3(arr)
    print(ans)


if __name__ == "__main__":
    t = int(input())
    for _ in range(t):
        solve()