Ivan unexpectedly saw a present from one of his previous birthdays. It is array of n numbers from 1 to 200. Array is old and some numbers are hard to read. Ivan remembers that for all elements at least one of its neighbours ls not less than it, more formally:

a_{1} ≤ a_{2},

a_{n} ≤ a_{n-1} and

a_{i} ≤ max(a_{i-1},    a_{i+1}) for all i from 2 to n-1.

Ivan does not remember the array and asks to find the number of ways to restore it. Restored elements also should be integers from 1 to 200. Since the number of ways can be big, print it modulo 998244353.

Input

First line of input contains one integer n (2 ≤ n ≤ 10^{5}) — size of the array.

Second line of input contains n integers a_{i} — elements of array. Either a_{i} = -1 or 1 ≤ a_{i} ≤ 200. a_{i} = -1 means that i-th element can't be read.

Output

Print number of ways to restore the array modulo 998244353.

Examples

Input

3
1 -1 2


Output

1


Input

2
-1 -1


Output

200

Note

In the first example, only possible value of a_{2} is 2.

In the second example, a_{1} = a_{2} so there are 200 different values because all restored elements should be integers between 1 and 200. 
import java.lang.*;
import java.math.*;
import java.util.*;
import java.io.*;

public class Main {
    void solve(){
        int n=ni();
        int a[]=new int[n+1];
        for(int i=1;i<=n;i++) a[i]=ni();
        long dp[][][]=new long[2][201][2];
        if(a[1]==-1){
            for(int i=1;i<=200;i++) dp[1][i][0]=1;
        }else {
            dp[1][a[1]][0]=1;
        }
        long pref[][]=new long[201][2];

        for(int i=2;i<=n;i++){
            for(int j=0;j<=200;j++) {
                dp[i%2][j][0]=dp[i%2][j][1]=0;
            }
            //Arrays.fill(pref,0);
            for(int j=1;j<=200;j++) {
                pref[j][0]=pref[j-1][0];
                pref[j][1]=pref[j-1][1];

                pref[j][0]=add(pref[j][0],dp[(i-1)%2][j][0]);
                pref[j][1]=add(pref[j][1],dp[(i-1)%2][j][1]);

            }
            if(a[i]==-1){
                for(int j2=1;j2<=200;j2++){
                    dp[i%2][j2][0]=add(pref[j2-1][0],pref[j2-1][1]);

                    dp[i%2][j2][1]=sub(pref[200][1],pref[j2][1]);
                    dp[i%2][j2][1]=add(dp[i%2][j2][1],dp[(i-1)%2][j2][0]);
                    dp[i%2][j2][1]=add(dp[i%2][j2][1],dp[(i-1)%2][j2][1]);

                }
            }else {
                int j2=a[i];
                dp[i%2][j2][0]=add(pref[j2-1][0],pref[j2-1][1]);

                dp[i%2][j2][1]=sub(pref[200][1],pref[j2][1]);
                dp[i%2][j2][1]=add(dp[i%2][j2][1],dp[(i-1)%2][j2][0]);
                dp[i%2][j2][1]=add(dp[i%2][j2][1],dp[(i-1)%2][j2][1]);
            }
        }
        long ans=0;
        if(a[n]!=-1){
            ans=dp[n%2][a[n]][1];
        }else {
            for(int j=1;j<=200;j++) ans=add(ans,dp[n%2][j][1]);
        }
        pw.println(ans);
    }
    long add(long x,long y){
        x+=y;
        if(x>=M) x-=M;
        return x;
    }
    long sub(long x,long y){
        x-=y;
        if(x<0) x+=M;
        return x;
    }


    long M= 998244353;
    InputStream is;
    PrintWriter pw;
    String INPUT = "";
    void run() throws Exception {
        is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
        pw = new PrintWriter(System.out);
        long s = System.currentTimeMillis();
        solve();
        pw.flush();
        if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
    }
    public static void main(String[] args) throws Exception { new Main().run(); }

    private byte[] inbuf = new byte[1024];
    public int lenbuf = 0, ptrbuf = 0;

    private int readByte() {
        if(lenbuf == -1)throw new InputMismatchException();
        if(ptrbuf >= lenbuf){
            ptrbuf = 0;
            try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
            if(lenbuf <= 0)return -1;
        }
        return inbuf[ptrbuf++];
    }

    private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
    private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }

    private double nd() { return Double.parseDouble(ns()); }
    private char nc() { return (char)skip(); }

    private String ns() {
        int b = skip();
        StringBuilder sb = new StringBuilder();
        while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }

    private char[] ns(int n) {
        char[] buf = new char[n];
        int b = skip(), p = 0;
        while(p < n && !(isSpaceChar(b))){
            buf[p++] = (char)b;
            b = readByte();
        }
        return n == p ? buf : Arrays.copyOf(buf, p);
    }

    private char[][] nm(int n, int m) {
        char[][] map = new char[n][];
        for(int i = 0;i < n;i++)map[i] = ns(m);
        return map;
    }

    private int[] na(int n) {
        int[] a = new int[n];
        for(int i = 0;i < n;i++)a[i] = ni();
        return a;
    }

    private int ni() {
        int num = 0, b;
        boolean minus = false;
        while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
        if(b == '-'){
            minus = true;
            b = readByte();
        }

        while(true){
            if(b >= '0' && b <= '9'){
                num = num * 10 + (b - '0');
            }else{
                return minus ? -num : num;
            }
            b = readByte();
        }
    }

    private long nl() {
        long num = 0;
        int b;
        boolean minus = false;
        while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
        if(b == '-'){
            minus = true;
            b = readByte();
        }

        while(true){
            if(b >= '0' && b <= '9'){
                num = num * 10 + (b - '0');
            }else{
                return minus ? -num : num;
            }
            b = readByte();
        }
    }
    private boolean oj = System.getProperty("ONLINE_JUDGE") != null;
    private void tr(Object... o) { if(INPUT.length() > 0)System.out.println(Arrays.deepToString(o)); }

}