#include <bits/stdc++.h>
#define _1 (__int128)1

using namespace std;
using ll = long long;

void FileIO (const string s) {
  freopen(string(s + ".in").c_str(), "r", stdin);
  freopen(string(s + ".out").c_str(), "w", stdout);
}

const int N = 2e5 + 10, mod = 998244353;

int n, a[N], b[N], m, inv[N], X[N], F[N], ans, mx[N], cnt;
bool f[N];

inline int C (int a, int b) {
  return (a >= b ? 1ll * F[a] * X[b] % mod * X[a - b] % mod : 0);
}

inline int A (int a, int b) {
  return (a >= b ? 1ll * F[a] * X[a - b] % mod : 0);
}

int qmod (int x, int y) {
  int ret = 1;
  while (y) ret = (y & 1 ? 1ll * ret * x % mod : ret), x = 1ll * x * x % mod, y >>= 1;
  return ret;
}

signed main () {
  ios::sync_with_stdio(0), cin.tie(0);
  // FileIO("");
  cin >> n;
  inv[1] = X[0] = F[0] = 1;
  for (int i = 2; i <= n; i++)
    inv[i] = 1ll * (mod - mod / i) * inv[mod % i] % mod;
  for (int i = 1; i <= n; i++)
    X[i] = 1ll * X[i - 1] * inv[i] % mod, F[i] = 1ll * F[i - 1] * i % mod;
  for (int i = 1; i <= n; i++)
    cin >> a[i], f[(a[i] != -1 ? a[i] : 0)] = 1, mx[i] = max(a[i], mx[i - 1]);
  for (int i = 1; i <= n; i++)
    if (!f[i])
      b[++m] = i;
  for (int i = 1; i <= n; i++) {
    if (a[i] == -1) {
      cnt++, ans = (ans + 1ll * (A(m, cnt) - A((lower_bound(b + 1, b + m + 1, mx[i]) - b - 1), cnt)) * A(m - cnt, m - cnt) % mod * qmod(cnt, mod - 2)) % mod;
    } else if (a[i] > mx[i - 1]) {
      ans = (ans + 1ll * A((lower_bound(b + 1, b + m + 1, a[i]) - b - 1), cnt) * A(m - cnt, m - cnt)) % mod;
    }
  }
  cout << ans;
  return 0;
}