#include<iostream>
#include<string>
#include<queue>
#include<vector>
#include<cassert>
#include<random>
#include<set>
#include<map>
#include<cassert>
#include<unordered_map>
#include<bitset>
#include<numeric>
#include<algorithm>
using namespace std;
using ll = long long;
const int inf=1<<30;
const ll INF=1LL<<62;
typedef pair<int,ll> P;
typedef pair<int,P> PP; 
const ll MOD=998244353;
const int dy[]={0,1,0,-1};
const int dx[]={1,0,-1,0};



const int mod = 998244353;
struct mint {
  long long x; // typedef long long long long;
  mint(long long x=0):x((x%mod+mod)%mod){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod-a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this;}
  mint operator+(const mint a) const { return mint(*this) += a;}//後ろのconstはメンバxを変更しないことを示す
  mint operator-(const mint a) const { return mint(*this) -= a;}
  mint operator*(const mint a) const { return mint(*this) *= a;}
  bool operator==(const mint a) const {return a.x==x;}
  mint pow(unsigned long long int t) const {
    assert(t>=0);
    if (!t) return 1;
    //aがtで割り切れない場合には t%=(mod-1)をして良い
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }

  // for prime mod
  mint inv() const { return pow(mod-2);}
  mint& operator/=(const mint a) { return *this *= a.inv();}
  mint operator/(const mint a) const { return mint(*this) /= a;}
};

std::istream& operator>>(std::istream& is, mint& a) { return is >> a.x;}
std::ostream& operator<<(std::ostream& os, const mint& a) { return os << a.x;}



struct combination {
  std::vector<mint> fact, ifact;
  combination(int n):fact(n+1),ifact(n+1) {
    assert(n < mod);
    fact[0] = 1;
    for (int i = 1; i <= n; ++i) fact[i] = fact[i-1]*i;
    ifact[n] = fact[n].inv();
    for (int i = n; i >= 1; --i) ifact[i-1] = ifact[i]*i;
  }
  mint operator()(int n, int k) {
    if (k < 0 || k > n) return 0;
    return fact[n]*ifact[k]*ifact[n-k];
  }
};

mint dp[2005][2005];

int main(){
    int N;
    cin>>N;
    string s;
    cin>>s;

    if(s[0]=='1'){
        dp[0][0]=N;
        for(int j=1;j<=N;j++){
            dp[0][j]=0;
        }
    }else{
        //s[0]=='0'
        for(int j=0;j<N;j++){
            dp[0][j]=1;
        }
    }

    for(int i=1;i<N;i++){

        if(s[i]=='1'){
            for(int j=0;j<=N;j++){
                int remain=N-(i+j);
                dp[i][j]=dp[i-1][j]*remain;
            }
        }else{
            vector<mint> sum_dp(N+1);
            sum_dp[0]=dp[i-1][0];
            for(int j=1;j<=N;j++){
                sum_dp[j]=sum_dp[j-1]+dp[i-1][j];
            }

            for(int j=0;j<=N;j++){
                dp[i][j]+=sum_dp[j];
                if(j-1>=0){
                dp[i][j-1]+=dp[i-1][j]*j;
                }
            }
        }
    }

    mint ans=dp[N-1][0];
    cout<<ans<<endl;

    
}