import sys

def solve():
    input_data = sys.stdin.read().split()
    if not input_data:
        return
    N = int(input_data[0])
    A = input_data[1]
    
    MOD = 998244353
    
    dp0 = 1 if A[0] == '0' else 0
    dp1 = 1
    
    for i in range(1, N):
        new_dp0 = dp0
        if A[i] == '0' and A[i-1] == '1':
            new_dp0 = (new_dp0 + dp1) % MOD
            
        new_dp1 = (dp1 + dp0) % MOD
        
        dp0 = new_dp0
        dp1 = new_dp1
        
    ans = dp0
    if A[-1] == '1':
        ans = (ans + dp1) % MOD
        
    print(ans)

if __name__ == '__main__':
    solve()