from sys import stdin
input=lambda :stdin.readline()[:-1]

n=int(input())
s=input()

mod=998244353
ans=0
pow2=[1]*(n+1)
for i in range(1,n+1):
  pow2[i]=pow2[i-1]*2%mod

for i in range(n):
  dp=[0]*(n+1)
  dp[0]=1
  cum=[0]*(n+2)
  cum[1]=1
  res=1
  for j in range(n):
    if j>=i and s[j-i]=='1':
      ans+=cum[j-i+1]*pow2[max(0,n-2-j)]%mod*pow2[i]
      ans%=mod
      dp[j+1]=cum[j+1]-cum[j-i+1]
    else:
      dp[j+1]=cum[j+1]
    cum[j+2]=cum[j+1]+dp[j+1]
    cum[j+2]%=mod

print(ans%mod)