#include <bits/stdc++.h>
using namespace std;
int tab[100002], dp[2][2][202], prefdp[2][2][202];
int mod = 998244353;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> tab[i];
  if (tab[0] == -1) {
    for (int i = 1; i <= 200; i++) dp[0][0][i] = 1;
  } else
    dp[0][0][tab[0]] = 1;
  for (int i = 1; i <= 200; i++)
    prefdp[0][0][i] = prefdp[0][0][i - 1] + dp[0][0][i];
  for (int i = 1; i < n; i++) {
    for (int j = 1; j <= 200; j++) {
      if (tab[i] == -1 || tab[i] == j) {
        dp[i % 2][0][j] =
            prefdp[(i + 1) % 2][0][j - 1] + prefdp[(i + 1) % 2][1][j - 1];
        dp[i % 2][1][j] =
            (0ll + prefdp[(i + 1) % 2][1][200] - prefdp[(i + 1) % 2][1][j - 1] +
             dp[(i + 1) % 2][0][j] + mod) %
            mod;
      } else {
        dp[i % 2][0][j] = 0;
        dp[i % 2][1][j] = 0;
      }
      dp[i % 2][0][j] %= mod;
      prefdp[i % 2][0][j] = prefdp[i % 2][0][j - 1] + dp[i % 2][0][j];
      prefdp[i % 2][1][j] = prefdp[i % 2][1][j - 1] + dp[i % 2][1][j];
      prefdp[i % 2][0][j] %= mod;
      prefdp[i % 2][1][j] %= mod;
    }
  }
  cout << prefdp[(n - 1) % 2][1][200];
}
