#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;
using ll = long long;

#include<queue>
#include<atcoder/modint>
using mint = atcoder::modint998244353;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int n;
    cin>>n;
    vector<int> a(n);
    int cnt = 0;
    for(int i = 0;i<n;i++){
        cin>>a[i];
        if(a[i]!=-1) a[i]--;
        if(a[i]==-1) cnt++;
    }
    vector<mint> fac(n+1,1),ifac(n+1,1);
    for(int i = 1;i<=n;i++) fac[i] = fac[i-1] * i;
    for(int i = 1;i<=n;i++) ifac[i] = fac[i].inv();

    mint ans = 0;

    auto comb = [&](int n,int r) -> mint {
        if(n<r) return 0;
        return fac[n] * ifac[r] * ifac[n-r];
    };

    {
        deque<int> b;
        vector<int> use(n,0);
        for(int i = 0;i<n;i++) if(a[i]!=-1) use[a[i]] = 1;
        for(int i = 0;i<n;i++) if(use[i]==0) b.push_back(i);
        int mx = 0;
        int res = cnt;
        for(int i = 0;i<n;i++){
            if(a[i]!=-1){
                mx = max(mx,a[i]);
                continue;
            }
            while(b.size()){
                int ni = b.front();
                if(ni<mx){
                    b.pop_front();
                    continue;
                }
                break;
            }
            if(b.size()==0) {
                res--;
                continue;
            }
            
            int left = cnt - b.size();
            int right = cnt - 1;

            int x = cnt - res ;

            mint tmp = comb(cnt-1,x).inv();
            tmp *= comb(right+1,x+1) - comb(left,x+1);
            tmp /= cnt;
            ans += tmp;
            res--;

        }
    }
    //cout<<(ans*fac[cnt]).val()<<endl;
    {
        vector<int> use(n,0);
        for(int i = 0;i<n;i++) if(a[i]!=-1) use[a[i]] = 1;
        vector<int> sum(n+1,0);
        for(int i = 0;i<n;i++) if(use[i]==0) sum[i+1]++;
        for(int i = 0;i<n;i++) sum[i+1] += sum[i];
        int left = 0;
        int mx = -1;
        for(int i = 0;i<n;i++){
            if(a[i]==-1){
                left++;
                continue;
            }
            mx = max(mx,a[i]);
            if(mx!=a[i]) continue;
            mint tmp = comb(cnt,left).inv();
            int all = sum[a[i]];
            tmp *= comb(all,left);
            ans += tmp;
        }  
    }
    ans *= fac[cnt];
    cout<<ans.val()<<endl;

}