#include<bits/stdc++.h>
using namespace std;
using ll=long long;

#include<atcoder/all>
using namespace atcoder;
using mint = modint998244353;
vector<mint> fact, factinv, inv;
const ll mod = 998244353;
void prenCkModp(ll n) {
    fact.resize(n + 5);
    factinv.resize(n + 5);
    inv.resize(n + 5);
    fact[0] = fact[1] = 1;
    factinv[0] = factinv[1] = 1;
    inv[1] = 1;
    for (ll i = 2; i < n + 5; i++) {
        fact[i] = (fact[i - 1] * i);
        inv[i] = mod - (inv[mod % i] * (mod / i));
        factinv[i] = (factinv[i - 1] * inv[i]);
    }

}

mint nCk(ll n, ll k) {
    if (n < k||k<0) return 0;
    return fact[n] * (factinv[k] * factinv[n - k]);
}
int main(){

    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    ll N;
    cin>>N;
    string S;
    cin>>S;
    vector<vector<mint>> DP(N+1,vector<mint>(N+1,0));
    vector<vector<mint>> SDP(N+1,vector<mint>(N+1,0));
    DP[0][0]=1;
    for(int i=0;i<=N;i++)SDP[0][i]=1;
    for(int i=0;i<N;i++){
        if(S[i]=='1'){
            for(int j=0;j<=i;j++){
                ll d=i-j;
                DP[i+1][j]+=DP[i][j]*(d+1);
            }
        }
        else{
            for(int j=1;j<=i+1;j++){
                DP[i+1][j]+=SDP[i][j-1];
                if(j!=1){
                    DP[i+1][j]+=DP[i][j-1]*(j-1);
                }
            }
        }
        SDP[i+1][0]=DP[i+1][0];
        for(int j=1;j<=N;j++){
            SDP[i+1][j]=DP[i+1][j]+SDP[i+1][j-1];
        }
    }
    // cout<<SDP[1][1].val()<<endl;
    cout<<SDP[N][N].val()<<endl;
}