// Problem: # 9489. 0100 Insertion
// Author: XZC(L_Wave)
// Language: Cpp/G++20
// Contest: 
// URL: https://qoj.ac/problem/9489
// Memory Limit: 1024 MB
// Time Limit: 1000 ms
// Create Time: not 2024-11-20 08:41:35, but 1926-08-17 11:45:14
// 
// Powered by CP Editor (https://cpeditor.org)

#include <bits/stdc++.h>
#define rep(i, a, b) for (int i = (a), i##ABRACADABRA = (b); i <= i##ABRACADABRA; i++)
#define drep(i, a, b) for (int i = (a), i##ABRACADABRA = (b); i >= i##ABRACADABRA; i--)
using namespace std;
using ll = long long;
constexpr ll mod=998244353;

template<typename T,int B>
class dArray{
  static_assert(B>=0,"dArray size must not be negative");
  T a[B+B+10];
public:
  T&operator[](int x){
    assert(-B<=x&&x<=B);
    return a[x+B+5];
  }
  T operator[](int x)const{
    assert(-B<=x&&x<=B);
    return a[x+B+5];
  }
  void read(){
    rep(i,-B,B)cin>>a[i+B+5];
  }
  void read(int L,int R){
    assert(-B<=L&&L<=B);
    assert(-B<=R&&R<=B);
    rep(i,L,R)cin>>a[i+B+5];
  }
  void print(char sep=' ',char end='\n')const{
    rep(i,-B,B)cout<<a[i+B+5]<<(i==B?end:sep);
  }
  void print(int L,int R,char sep=' ',char end='\n')const{
    assert(-B<=L&&L<=B);
    assert(-B<=R&&R<=B);
    rep(i,L,R)cout<<a[i+B+5]<<(i==B?end:sep);
  }
};
dArray<ll,505>dp[2][2][505];
int n;
ll res;
char s[505];

int main() {
  scanf("%d%s",&n,s+1);
  reverse(s+1,s+n+1);
  dp[0][0][0][0]=1;
  rep(i,1,n){
    rep(v,0,1)rep(j,0,i/3+1)rep(k,-i,j)dp[i&1][v][j][k]=0;
    if (s[i]!='0'){
      // Place 1
      rep(j,0,(i-1)/3+1)rep(k,-i+1,j)
        if (k+2<=j)(dp[i&1][1][max(j,k+3)][k+3]+=dp[(i-1)&1][0][j][k])%=mod;
    }
    if (s[i]!='1'){
      // Place 0
      // cout<<(i-1)/3+1<<'\n';
      rep(j,0,(i-1)/3+1)rep(k,-i+1,j){
        (dp[i&1][0][j][k-1]+=dp[(i-1)&1][1][j][k]+dp[(i-1)&1][0][j][k])%=mod;
        // cout<<j<<' '<<k<<'\n';
      }
    }
    // rep(j,0,i/3+1)rep(k,-i,j)cout<<i<<' '<<j<<' '<<k<<' '<<dp[i&1][0][j][k]<<' '<<dp[i&1][1][j][k]<<'\n';
  }
  rep(i,0,n/3+1)(res+=dp[n&1][0][i][0])%=mod;
  printf("%lld\n",res);
  return 0;
}