#include<bits/stdc++.h>
using namespace std;

const int MAXN = 200005, MOD = 998244353;

int n, a[MAXN], f[MAXN], ans, Max, cnt, sum[MAXN], res[MAXN], inv[MAXN], Inv[MAXN];
vector<int> pos;

int A(int n, int m) {
  return (n < m ? 0 : 1ll * f[n] * Inv[n - m] % MOD);
}

int C(int n, int m) {
  return (n < m ? 0 : 1ll * f[n] * Inv[m] % MOD * Inv[n - m] % MOD);
}

int Pow(int a, int b) {
  int ret = 1;
  for(; b; a = 1ll * a * a % MOD, b >>= 1) {
    if(b & 1) {
      ret = 1ll * ret * a % MOD;
    }
  }
  return ret;
}

int Calc(int n, int x, int a) {
  return (1ll * f[a] * (x - a) % MOD * Pow(f[a - x], MOD - 2) % MOD + 1ll * f[n + 1] * (n - x + 1) % MOD * Pow(f[n - x + 1], MOD - 2) % MOD) % MOD * 1ll * Pow(x + 1, MOD - 2) % MOD;
}

int main() {
  ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  cin >> n;
  f[0] = inv[1] = Inv[0] = res[0] = 1;
  for(int i = 1; i < MAXN; ++i) {
    f[i] = 1ll * f[i - 1] * i % MOD;
    res[i] = (res[i - 1] + Pow(f[i], MOD - 2)) % MOD;
    inv[i] = (i > 1 ? 1ll * (MOD - MOD / i) * inv[MOD % i] % MOD : 1);
    Inv[i] = 1ll * Inv[i - 1] * inv[i] % MOD;
  }
  for(int i = 1; i <= n; ++i) {
    cin >> a[i];
    if(a[i] != -1) {
      sum[a[i]] = 1;
    }
  }
  for(int i = 1; i <= n; ++i) {
    if(!sum[i]) {
      pos.emplace_back(i);
    }
    sum[i] = sum[i - 1] + !sum[i];
  }
  for(int i = 1; i <= n; ++i) {
    Max = max(Max, a[i]), cnt += (a[i] == -1);
    if(a[i] == -1) {
      int x = lower_bound(pos.begin(), pos.end(), Max) - pos.begin();
      if(x == pos.size()) {
        continue;
      }
      ans = (ans + 1ll * Calc(sum[n] - 1, cnt - 1, max(cnt - 1, x)) % MOD * f[sum[n] - cnt] % MOD) % MOD;
    }else if(a[i] == Max) {
      ans = (ans + 1ll * A(sum[Max], cnt) * f[sum[n] - cnt] % MOD) % MOD;
    }
  }
  cout << ans;
  return 0;
}