I,R=input,range
N=int(I())
M=R(N)
A=[[[0,0]for j in R(N+1)]for i in R(N+1)]
S=I()
P=998244353
for h in R(N-1,-1,-1):
	s,B=S[h]>"0",[[[0,0]for j in R(N+1)]for i in R(N+1)]
	if h<N-1:
		for i in M:
			for k in [0,i+1]:
				for j in M:
					B[k][j][[0,s][j==k]]+=A[i][j][0]
					B[k][j][1]+=A[i][j][1]
	else:
		for j in M:B[0][j][[0,s][j<1]]=1
	A=B
print(sum(pow(2,j,P)*sum(A[i][j][1]for i in M)for j in M)%P)