#include <bits/stdc++.h> using namespace std; typedef long long ll; typedef pair<int,int> P; #define REP(i,n) for(ll i=0;i<ll(n);i++) const ll MOD=998244353; ll dp[2][200010]; int main(void){ cin.tie(nullptr); ios_base::sync_with_stdio(false); ll i,j; ll N; string S; cin >> N >> S; vector<ll> v; REP(i,N) if(S[i]=='1') v.push_back(i); ll n=v.size(); if(n==0 || n==1){ cout << n << endl; return 0; } vector<ll> u; for(i=1;i<n;i++){ u.push_back(v[i]-v[i-1]); } ll m=u.size(); dp[1][0]=1; for(i=1;i<=m;i++){ dp[0][i]=dp[0][i-1]+dp[1][i-1]; dp[0][i]%=MOD; dp[1][i]=(dp[0][i-1]+dp[1][i-1])*u[i-1]; dp[1][i]%=MOD; } cout << (dp[0][m]+dp[1][m])%MOD << endl; return 0; }