#include<bits/stdc++.h>
#define int long long
using namespace std;
#define fi first
#define sc second
#define pii pair<int,int>
#define pb push_back
#define umap unordered_map
#define mset multiset
#define pq priority_queue
#define ull unsigned long long
#define i128 __int128
const int maxn=2e5+10;
const int mod=998244353;
int n,a[maxn],fr[maxn],ifr[maxn],vis[maxn];
vector<int> vec;
int quickpow(int x,int y){
    int p=1;
    for(int i=y;i;i>>=1) p=(p*((i&1)?x:1))%mod,x=(x*x)%mod;
    return p;
}
int inv(int x){
    return quickpow(x,mod-2);
}
void solve(){
    cin>>n,fr[0]=1;
    for(int i=1;i<=n;i++) cin>>a[i],vis[a[i]]=1;
    for(int i=1;i<=n;i++) fr[i]=(fr[i-1]*i)%mod;
    ifr[n]=inv(fr[n]);
    for(int i=n-1;~i;i--) ifr[i]=(ifr[i+1]*(i+1))%mod;
    for(int i=1;i<=n;i++) if(!vis[i]) vec.pb(i);
    int maxx=0,res=0,cnt=0;
    for(int i=1;i<=n;i++){
        maxx=max(maxx,a[i]);
        int pos=lower_bound(vec.begin(),vec.end(),maxx)-vec.begin();
        if(a[i]==-1){
            cnt++;
            int num=fr[vec.size()]*ifr[vec.size()-cnt]%mod;
            if(pos>=cnt) num=(num-fr[pos]*ifr[pos-cnt]%mod+mod)%mod;
            num=(num*inv(cnt)%mod*fr[vec.size()-cnt])%mod,res=(res+num)%mod;
        }
        else if(a[i]==maxx){
            if(pos>=cnt) res=(res+fr[pos]*ifr[pos-cnt]%mod*fr[vec.size()-cnt]%mod)%mod;
        }
    }
    cout<<res<<endl;
}
signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0),cout.tie(0);
    int t=1;
    // cin>>t;
    while(t--) solve();
    return 0;
}
/*
Samples
input:

output:

THINGS TODO:
??freopen???????
????
????????????
*/