#include<bits/stdc++.h>

using namespace std;

const int N = 2e5 + 5;
const int mod = 998244353;

int n, a[N];
bool vis[N];
vector<int> s;
long long pl[N], inv[N], ipl[N];

void init(int inf){
  pl[0] = pl[1] = 1, inv[0] = inv[1] = 1, ipl[0] = ipl[1] = 1;
  for(int i = 2; i <= inf; i++){
    pl[i] = pl[i - 1] * i % mod;
    inv[i] = (mod - mod / i) * inv[mod % i] % mod;
    ipl[i] = ipl[i - 1] * inv[i] % mod;
  }
}

long long A(long long n, long long m){
  if(m > n) return 0;
  if(n < 0 || m < 0) return 0;
  return pl[n] * ipl[n - m] % mod;
}

int main(){
  ios::sync_with_stdio(0), cin.tie(0);
  cin >> n;
  int sum = 0;
  for(int i = 1; i <= n; i++){
    cin >> a[i];
    if(a[i] >= 1) vis[a[i]] = 1;
    sum += (a[i] < 0);
  }
  init(n);
  for(int i = 1; i <= n; i++){
    if(!vis[i]) s.push_back(i);
  }
  long long ans = 0;
  for(int i = 1, cnt = 0, maxx = 0; i <= n; i++){
    if(a[i] >= 0){
      if(a[i] > maxx){
        int l = lower_bound(s.begin(), s.end(), a[i]) - s.begin();
        ans = (ans + A(l, cnt) * pl[sum - cnt] % mod) % mod;
      }
    }
    else{
      /*for(int j = lower_bound(s.begin(), s.end(), maxx + 1) - s.begin(); j < s.size(); j++){
        ans = (ans + A(j, cnt) * pl[sum - cnt - 1] % mod) % mod;
      }*/
      int l = lower_bound(s.begin(), s.end(), maxx + 1) - s.begin();
      ans = (ans + (A(s.size(), cnt + 1) - A(l, cnt + 1) + mod) % mod * inv[cnt + 1] % mod * pl[sum - cnt - 1] % mod) % mod;
    }
    cnt += (a[i] < 0), maxx = max(maxx, a[i]);
  }
  cout << ans;
  return 0;
}
/*
4
1 -1 3 -1
6
2 4 5 3 6 1
17
-1 -1 8 2 10 9 12 -1 7 -1 -1 -1 11 -1 13 -1 -1
*/