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

  static const long long MOD = 998244353;

  int main() {
      ios::sync_with_stdio(false);
      cin.tie(nullptr);

      int N;
      string A;
      cin >> N >> A;

      long long dp0 = (A[0] == '0') ? 1 : 0; // B1=0 allowed only if A1=0
      long long dp1 = 1;                      // B1=1 always allowed

      for (int i = 0; i < N - 1; i++) {
          long long ndp1 = (dp0 + dp1) % MOD;
          long long ndp0 = dp0;
          if (A[i] == '1' && A[i + 1] == '0') {
              ndp0 = (ndp0 + dp1) % MOD;
          }
          dp0 = ndp0 % MOD;
          dp1 = ndp1 % MOD;
      }

      long long ans = dp0;
      if (A[N - 1] == '1') ans = (ans + dp1) % MOD; // BN=1 allowed only if AN=1

      cout << ans % MOD << '\n';
      return 0;
  }