#include<cstdio>

 #include<cstring>

 #include<string>

 #include<cmath>

 #include<iostream>

 #include<algorithm>

 #include<map>

 #include<set>

 #include<queue>

 #include<vector>

 using namespace std;

 typedef long long ll;

 typedef unsigned int uint;

 typedef unsigned long long ull;

 typedef pair<int,int> PII;

 typedef vector<int> VI;

 #define fi first

 #define se second

 #define MP make_pair

 #define N  100010

 #define M  200

 #define MOD 998244353

 #define eps 1e-8

 #define pi acos(-1)

 ll dp[N][M+][],tmp;

 int a[N];

 int main()

 {

     //freopen("D.in","r",stdin);

     //freopen("D.out","w",stdout);

     int n;

     scanf("%d",&n);

     for(int i=;i<=n;i++) scanf("%d",&a[i]);

     for(int i=;i<=M;i++)

     {

         if(a[]==-||i==a[]) dp[][i][]=;

          else dp[][i][]=;

     }

     tmp=;

     for(int i=;i<=n;i++)

     {

         for(int j=;j<=M;j++)

         {

              if(a[i]==-||j==a[i]) dp[i][j][]=(dp[i-][j][]+dp[i-][j][]+dp[i-][j][])%MOD;

                else dp[i][j][]=;

         }

         tmp=;

         for(int j=;j<=M;j++)

         {

              if(a[i]==-||j==a[i]) dp[i][j][]=tmp;

               else dp[i][j][]=;

              tmp=(tmp+dp[i-][j][]+dp[i-][j][]+dp[i-][j][])%MOD;

         }

         tmp=;

         for(int j=M;j>=;j--)

         {

             if(a[i]==-||j==a[i]) dp[i][j][]=tmp;

              else dp[i][j][]=;

             tmp=(tmp+dp[i-][j][]+dp[i-][j][])%MOD;

         }

     }

     ll ans=;

     for(int i=;i<=M;i++) ans=(ans+dp[n][i][]+dp[n][i][])%MOD;

     printf("%lld\n",ans);

      return ;

 }