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

using namespace std;
using namespace atcoder;
using ll = long long;
using mint = modint998244353;
const int MX = 1000010;
mint f[MX],inv[MX],fi[MX];
constexpr ll mod = 998244353;
void solve(){
    inv[1] = 1;
    for(int i=2;i<MX;i++){
        inv[i] = mod - (mod/i)*inv[mod%i];
    }
    f[0] = fi[0] = 1;
    for(int i=1;i<MX;i++){
        f[i] = f[i-1]*i;
        fi[i] = fi[i-1]*inv[i];
    }
}

mint nck(ll n, ll k){
    if(n<0 || k<0 || n<k) return 0;
    return f[n]*fi[k]*fi[n-k];
}

mint pw(mint a,ll x){
    mint ret = 1;
    while(x){
        if(x&1) (ret *= a);
        (a *= a); x /= 2;
    }
    return ret;
}

int a[200010],noUse[200010];
bool b[200010];
int main(){
    solve();
    int i,n; cin >> n;
    for(i=0;i<n;i++) cin >> a[i];
    int al = 0;
    for(i=1;i<=n;i++) noUse[i] = 1;
    for(i=0;i<n;i++){
        if(a[i]==-1) al++;
        else noUse[a[i]] = 0;
    }
    for(i=1;i<=n;i++) noUse[i] += noUse[i - 1];
    for(i=n + 1;i>=1;i--) noUse[i] = noUse[i - 1];
    for(i=0;i<n;i++){
        if(a[i]!=-1) b[a[i]] = true;
    }
    int no_exist_mx = -1;
    for(i=1;i<=n;i++){
        if(!b[i]) no_exist_mx = max(no_exist_mx,i);
    }
    mint ans = 0;
    mint ans2 = 0;
    int mx = -1,c = 0;
    for(i=0;i<n;i++){
        if(a[i]==-1){
        	if(mx<n){
                int l = noUse[mx + 1],r = noUse[no_exist_mx];
                // cout << "l == " << l << " r == " << r << endl;
                // sum_{l<=x<=r} nck(x,c) = nck(r,c + 1) - nck(l,c + 1) 
                ans += (nck(r + 1,c + 1) - nck(l,c + 1))*f[c]*f[al - c - 1];
                // int cnt = 0;
                // for(int j=1;j<=mx;j++) cnt += !b[j];
                // for(int j=max(0,mx) + 1;j<=n;j++){
                //     if(!b[j]){
                //         cout << "cnt == " << cnt << endl;
                //         // cout << j << " xx " << (nck(cnt,c)*f[c]*f[al - c - 1]).val() << "\n";
                //         ans2 += nck(cnt,c)*f[c]*f[al - c - 1];
                //         cnt++;
                //     }
                // }
                // if(ans.val()!=ans2.val()){
                //     cout << mx << " " << l << " " << r << " " << c << " " << i << endl;
                //     cout << cnt << endl;
                //     cout << ans.val() << " " << ans2.val() << endl;
                //     assert(false);
                // }
        	}
        }else{
            if(mx<a[i]){
                ans += nck(noUse[a[i]],c)*f[c]*f[al - c];
                ans2 += nck(noUse[a[i]],c)*f[c]*f[al - c];
            }
        }
        if(a[i]==-1) c++;
        mx = max(mx,a[i]);
        //cout << "ans == " << ans.val() << "\n";
    }
    cout << ans.val() << "\n";
    // cout << ans2.val() << "\n";
}