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

#define rep(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rrep(i, a, b) for (int i = (int)(a); i > (int)(b); i--)
#define ll long long
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define PQ priority_queue<int, vector<int>, greater<int>>
#define PQ_g priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>>
#define chmin(a, b) a = min(a, b)
#define chmax(a, b) a = max(a, b)
const int d4[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
const int d8[8][2] = {{0, 1}, {1, 1}, {1, 0}, {1, -1}, {0, -1}, {-1, -1}, {-1, 0}, {-1, 1}};
void Yes(bool b) {cout << (b ? "Yes" : "No") << endl;}

int main() {
    int n; cin >> n;
    string a; cin >> a;
    ll const MOD = 998244353LL;
    a = '1' + a + '0';
    ll ans = 1LL;
    ll cnt = 1;
    bool flg0 = false, flg1 = false;
    vector<ll> bound10;
    rep(i, 0, a.size() - 1) {
        if (a[i] == '1' && a[i + 1] == '0') bound10.push_back((ll)i);
    }
    rep(i, 0, bound10.size() - 1) {
        ans *= bound10[i + 1] - bound10[i] + 1LL;
        ans %= MOD;
    }

    cout << ans << endl;
}