#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
const int mod = 998244353;
//using mint = modint1000000007;
//const int mod = 1000000007;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int t; cin >> t;
	while (t--) {
		int n, m; cin >> n >> m;
		vector<int>x(n);
		rep(i, n)cin >> x[i];
		int i = find(all(x), -1) - x.begin();
		if (n == i) {
			int ans = 0, now = 0;
			rep(j, x.size()) {
				now = (now + x[j]) % m;
				if (now)ans++;
			}
			if (now)ans = 0;
			cout << ans << endl;
			continue;
		}
		int j = n - 1;
		while (-1 != x[j])j--;
		int cnt = count(all(x), -1);
		mint ans = 0;
		if (i != j)ans = mint(j - i) *(m - 1)*mint(m).pow(cnt - 2);
		rep(t, 2) {
			int now = 0;
			rep(i, x.size()) {
				if (-1 == x[i])break;
				now = (now + x[i]) % m;
				if (0 != now)ans += pow_mod(m, cnt - 1, mod);
			}
			reverse(all(x));
		}
		cout << ans.val() << endl;
	}
	return 0;
}