#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint998244353;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int tt;
  cin >> tt;
  while (tt--) {
    int n;
    cin >> n;
    n++;
    VI a(n), pos(n, -1);
    a[0] = 0, pos[0] = 0;
    for (int i = 1; i < n; i++) {
      cin >> a[i];
      if (a[i] != -1) pos[a[i]] = i;
    }
    VI vac(n + 1);
    rep(i, n) vac[i+1] = vac[i] + (a[i] == -1);
    vector<mint> dp(n);
    dp[0] = 1;
    int used = 0;
    rep(v, n) if (v) {
      rrep(i, n) if (mint c = dp[i]; c.val()) {
        dp[i] = 0;
        if (pos[v] == -1) {
          int rest = vac[i + 1] - used;
          dp[i] += rest * c;
          if (i + 1 < n && a[i+1] == -1) dp[i+1] += c;
          if (i + 2 < n && a[i+2] == -1) dp[i+2] += c;
        } else if (pos[v] <= i + 2) {
          dp[max(i, pos[v])] += c;
        }
      }
      if (pos[v] == -1) used++;
      // rep(i, n) cout << dp[i].val() << " \n"[i + 1 == n];
    }
    mint ans = accumulate(all(dp), mint());
    cout << ans.val() << '\n';
  }
}