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.io.*;
import java.util.*;

public class Solution{
    InputStream is;
    static PrintWriter out;
    String INPUT = "";
    static long mod = 998244353L;
    
    int n;
    long[][][] dp;
    int[] a;
    public void solve(){
        n = ni();
        a = na(n);
        dp = new long[n+1][201][2];

        if(a[0] == -1){
	        for(int v = 1; v <= 200; v++){
				dp[0][v][0] = 1 + dp[0][v-1][0];
	        }
	    }
	    else{
	    	for(int v = a[0]; v <= 200; v++)
	    		dp[0][v][0] = 1;
	    }
        for(int i = 1; i < n; i++){
        	if(a[i] != -1){
        		int v = a[i];
        		for(int ok = 0; ok < 2; ok++){
        			if(ok == 1){
    					dp[i][v][ok] = ((dp[i-1][200][ok]-dp[i-1][v-1][ok]+mod) + (dp[i-1][v][ok-1]-dp[i-1][v-1][ok-1]+mod));
    				}
    				else{
    					dp[i][v][ok] = (dp[i-1][v-1][ok] + dp[i-1][v-1][ok+1]);
    				}
    				dp[i][v][ok] = (dp[i][v-1][ok] + dp[i][v][ok])%mod;
        		}

        		continue;
        	}
        	for(int v = 1; v <= 200; v++){
        		for(int ok = 0; ok < 2; ok++){
        			if(a[i] == -1 || (a[i] == v)){
        				if(ok == 1){
        					dp[i][v][ok] = ((dp[i-1][200][ok]-dp[i-1][v-1][ok]+mod) + (dp[i-1][v][ok-1]-dp[i-1][v-1][ok-1]+mod));
        				}
        				else{
        					dp[i][v][ok] = (dp[i-1][v-1][ok] + dp[i-1][v-1][ok+1]);
        				}
        			}

        			dp[i][v][ok] = (dp[i][v-1][ok] + dp[i][v][ok])%mod;
        		}
        	}

        	

        }

        out.println(dp[n-1][200][1]);
    }
    

    void run(){
        is = new DataInputStream(System.in);
        out = new PrintWriter(System.out);
        int t=1;while(t-->0)solve();
        out.flush();
    }
    public static void main(String[] args)throws Exception{new Solution().run();}
    long mod(long v, long m){if(v<0){long q=(Math.abs(v)+m-1L)/m;v=v+q*m;}return v%m;}
    long mod(long v){if(v<0){long q=(Math.abs(v)+mod-1L)/mod;v=v+q*mod;}return v%mod;}
    //Fast I/O code is copied from uwi code.
    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();
        }
    }
    static  int i(long x){return (int)Math.round(x);}
    static class Pair implements Comparable<Pair>{
        long fs,sc;
        Pair(long a,long b){
            fs=a;sc=b;
        }
        public int compareTo(Pair p){
            if(this.fs>p.fs)return 1;
            else if(this.fs<p.fs)return -1;
            else{
                return i(this.sc-p.sc);
            }
            //return i(this.sc-p.sc);
        }
        public String toString(){
            return "("+fs+","+sc+")";
        }    
    }
    
}