def solve():
    N, M = map(int, input().split())
    X = list(map(int, input().split()))
    Mod = 998244353

    Q = X.count(-1)
    if Q == 1:
        i = X.index(-1)
        X[i] = (- sum(X[j] for j in range(N) if j != i)) % M

    if -1 not in X:
        if sum(X) % M != 0:
            return 0

        cum = 0
        k = 0
        for x in X:
            cum += x; cum %= M
            if cum == 0:
                k += 1
        return N - k

    left = min(i for i in range(N) if X[i] == -1)
    right = max(i for i in range(N) if X[i] == -1)

    cum = 0
    S = 0
    M_pow_Q1 = pow(M, Q - 1, Mod); M_pow_Q2 = pow(M, Q - 2, Mod)

    for i in range(N):
        if i < left:
            cum += X[i]; cum %= M
            if cum == 0:
                S += M_pow_Q1
        elif left <= i < right:
            S += M_pow_Q2
        else:
            if i == right:
                lazy = sum(X[i] for i in range(left, right) if X[i] != -1)
                cum += lazy
            else:
                cum += X[i]
            cum %= M
            if cum == 0:
                S += M_pow_Q1

    return (N * M_pow_Q1 - S) % Mod

#==================================================
import sys
input = sys.stdin.readline
write = sys.stdout.write

T = int(input())
write("\n".join(map(str, [solve() for _ in range(T)])))