#include <bits/stdc++.h>
using namespace std;
const int N = 100050, M = 200, P = 998244353;
int n, a[N];
int f[N][M + 5], g[N][M + 5];
int sf[M + 5], sg[M + 5];
int main() {
  scanf("%d", &n);
  for (int i = (1); i <= (n); ++i) scanf("%d", &a[i]);
  if (a[1] == -1)
    for (int i = (1); i <= (M); ++i) f[1][i] = 1;
  else
    f[1][a[1]] = 1;
  for (int i = (1); i <= (n - 1); ++i) {
    sf[0] = sg[0] = 0;
    for (int j = (1); j <= (M); ++j) {
      sf[j] = (sf[j - 1] + f[i][j]) % P;
      sg[j] = (sg[j - 1] + g[i][j]) % P;
    }
    int p1, p2;
    if (a[i + 1] == -1) {
      p1 = 1;
      p2 = M;
    } else
      p1 = p2 = a[i + 1];
    for (int j = (p1); j <= (p2); ++j) {
      f[i + 1][j] = (sf[j - 1] + sg[j - 1]) % P;
      g[i + 1][j] = (f[i][j] + (sg[M] + P - sg[j - 1]) % P) % P;
    }
  }
  int ans = 0;
  for (int i = (1); i <= (M); ++i) (ans += g[n][i]) %= P;
  printf("%d\n", ans);
  return 0;
}
