#include<stdio.h>
#define M 505
int f[505][125][255],n;
char s[M];
constexpr int mod=998244353;
int main(){
	scanf("%d%s",&n,s);
	f[0][0][0]=1;
	for(int i=0;i<n;++i) if(s[i]!='1'){
		for(int j=0;j<=n/4;++j) for(int k=0;k<=n/2;++k) if(f[i][j][k]){
			if(k) (f[i+1][j][k-1]+=f[i][j][k])%=mod;
			else (f[i+1][j+1][k]+=f[i][j][k])%=mod;
			if(i+1<n&&s[i+1]!='0'){
				if(k==1&&j) (f[i+2][j-1][k+1]+=f[i][j][k])%=mod;
				else (f[i+2][j][k+2]+=f[i][j][k])%=mod;
			}
		}
	}
	printf("%d",f[n][0][0]);
}