import sys
input = sys.stdin.readline

N=int(input())
S=input().strip()

mod=998244353

SET=set()
for i in range(N):
    if S[i]=="1":
        SET.add(i)

ANS=0

for i in range(N):
    USED=[0]*(N+N+1)
    NOUSED=[0]*(N+N+1)
    NOUSED[0]=1

    for j in range(N-1):
        USED[j+1]+=USED[j]
        NOUSED[j+1]+=NOUSED[j]
        
        if j-i in SET:
            USED[j+1]+=NOUSED[j-i]+USED[j]
            NOUSED[j+1]+=NOUSED[j]-NOUSED[j-i]
        else:
            USED[j+1]+=USED[j]
            NOUSED[j+1]+=NOUSED[j]

        USED[j+1]%=mod
        NOUSED[j+1]%=mod

    if N-1-i in SET:
        ANS+=pow(2,i,mod)*(USED[N-1]+NOUSED[N-1-i])
    else:
        ANS+=pow(2,i,mod)*USED[N-1]

    ANS%=mod

    #print(ANS,USED,NOUSED)

print(ANS%mod)