#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
#define fix(x) fixed << setprecision(x)
#define asc(x) x, vector<x>, greater<x>
#define rep(i, n) for(ll i = 0; i < n; ++i)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
constexpr ll INFLL = (1LL << 62), MOD = 998244353;
constexpr int INF = (1 << 30);

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n;
    string s;
    cin >> n >> s;
    vector<ll> dp(n+2,0);
    dp[1] = 1;
    int now = 0, r = n-1;
    while(r>=0 && s[r]=='0') r--;
    for(int i=0;i<=r;i++){
        if(s[i]=='1') now = i+1;
        dp[i+2] = (dp[i+1] + dp[now]) % MOD;
    }
    cout << dp[r+1] << '\n';
    return 0;
}