#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <atcoder/modint>
using namespace std;
using i64 = long long;
using u64 = unsigned long long;
#define rep(i,n) for(i64 i=0; i<(i64)(n); i++)
#define repr(i,n) for(i64 i=(i64)(n)-1; i>=0; i--)
const i64 INF = 1001001001001001001;
using Modint = atcoder::static_modint<998244353>;

int main(){
    ios::sync_with_stdio(false); cin.tie(nullptr);
    int N; cin >> N;
    string S; cin >> S;
    Modint q0 = 1, q1 = 0;
    for(char c : S){
        if(c == '1'){
            q1 += q0;
            q0 = 0;
        }
        q0 += q1;
    }
    cout << q1.val() << endl;
    return 0;
}