#include <iostream>
#include <string>
#include <algorithm>
#include <vector>

int main(void)
{
  int N;
  std::string S;
  std::cin >> N >> S;

  std::vector<int> zeros;
  int count = 0;
  for (auto& c : S)
  {
	  if (c == '0') { count++; }
	  if (c == '1')
	  {
		  if (zeros.empty())
		  {
			  zeros.push_back(1);
		  }
		  else
		  {
			  zeros.push_back(count + 2);
		  }
		  count = 0;
	  }
  }

  if (zeros.empty())
  {
	  std::cout << '0' << std::endl;
	  return 0;
  }

  long long ans = 1;
  for (auto& e : zeros)
  {
	  ans *= e;
	  ans %= 998244353;
  }
  std::cout << ans << std::endl;

  return 0;
}