#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
using mint = modint998244353;

int N;
string S;
const ll mod = 998244353;

int main() {
  cin >> N >> S;
  vector dp(N + 1, vector(2, 0LL));
  dp[0][0] = 1;
  for (int i = 0; i < N; i++) {
    if (S[i] == '0') dp[i + 1][0] += dp[i][0] + dp[i][1];
    else dp[i + 1][1] += dp[i][0] + dp[i][1];
    dp[i + 1][1] += dp[i][1];
    dp[i + 1][0] %= mod;
    dp[i + 1][1] %= mod;
  }
  cout << dp[N][1] << endl;
  return 0;
}