#include <iostream>
#include <vector>
#include <atcoder/modint>

using namespace std;
using namespace atcoder;
using mint = modint998244353;
mint dp[5010][5010];
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t; cin >> t;
    while(t){
        t--;
        int i,j,n; cin >> n;
        vector<int> a(n);
        for(i=0;i<n;i++) cin >> a[i];
        vector<int> b(n + 1,-1);
        for(i=0;i<n;i++){
            if(a[i]!=-1) b[a[i]] = i + 1;
        }
        for(i=0;i<=n;i++){
            for(j=0;j<=n;j++) dp[i][j] = 0;
        }
        dp[0][0] = 1;
        for(i=1;i<=n;i++){
            for(j=1;j<=n;j++){
                if(b[i]==-1){
                    if(a[j - 1]==-1){
                        dp[i][j] += dp[i - 1][j - 1];
                        if(j>=2) dp[i][j] += dp[i - 1][j - 2];
                    }
                    dp[i][j] += dp[i - 1][j]*(j - i + 1);
                }else{
                    if(b[i]==j){
                        dp[i][j] += dp[i - 1][j - 1];
                        if(j>=2) dp[i][j] += dp[i - 1][j - 2];
                    }
                    if(b[i]<=j) dp[i][j] += dp[i - 1][j];
                }
            }
        }
        mint ans = dp[n][n];
        cout << ans.val() << "\n";
    }
}