// 私は猫です

#include<bits/stdc++.h>
#define ull unsigned long long
#define ll long long
#define pb push_back
#define mkp make_pair
#define fi first
#define se second
#define inf 1000000000
#define infll 1000000000000000000ll
#define pii pair<int,int>
#define rep(i,a,b,c) for(int i=(a);i<=(b);i+=(c))
#define per(i,a,b,c) for(int i=(a);i>=(b);i-=(c))
#define F(i,a,b) for(int i=a,i##end=b;i<=i##end;i++)
#define dF(i,a,b) for(int i=a,i##end=b;i>=i##end;i--)
#define cmh(sjy) while(sjy--)
#define lowbit(x) (x&(-x))
#define HH printf("\n")
#define eb emplace_back
#define poly vector<int>
using namespace std;
ll read(){
	ll x=0,f=1;char c=getchar();
	while(c<'0'||c>'9'){if(c=='-') f=-1;c=getchar();}
	while(c>='0'&&c<='9') x=(x<<3)+(x<<1)+(c^48),c=getchar();
	return x*f;
}
const int mod=998244353,maxn=1100005;
inline int qpow(int x,ll y){
	int rt=1;
	for(;y;y>>=1,x=1ll*x*x%mod) if(y&1) rt=1ll*rt*x%mod;
	return rt;
}
inline void inc(int &x,const int y){ x=(x+y>=mod)?(x+y-mod):(x+y); }
inline void dec(int &x,const int y){ x=(x>=y)?(x-y):(x+mod-y); }
inline void mul(int &x,const int y){ x=1ll*x*y%mod; }
inline int add(const int x,const int y){ return (x+y>=mod)?(x+y-mod):(x+y); }
inline int sub(const int x,const int y){ return (x>=y)?(x-y):(x+mod-y); }
inline int prod(const int x,const int y){ return 1ll*x*y%mod; }
inline void chkmax(int &x,const int y){ x=max(x,y); }
inline void chkmin(int &x,const int y){ x=min(x,y); }
int n,tr[20][2],f[maxn][16][2];
char str[maxn];
void solve(){
	n=read(),f[0][1][0]=1;
	F(s,0,15){
		int val=0;
		if((s&1)||(s&4))val|=2;
		if(s&2)val|=4;
		tr[s][0]=val;
	}
	F(s,0,15){
		int val=0;
		if(s&2)val|=9;
		if(s&8)val|=2;
		tr[s][1]=val;
	}
	scanf("%s",str+1);
	F(i,1,n){
		F(s,0,15)F(j,0,1)f[i][s][j]=f[i-1][s][j];
		if(str[i]!='1') F(s,0,15)F(j,0,1)inc(f[i][tr[s][0]][j],f[i-1][s][j^1]);
		if(str[i]!='0') F(s,0,15)F(j,0,1)inc(f[i][tr[s][1]][j],f[i-1][s][j^1]);
	}
	int ans=1;
	F(s,0,15)if(!(s&1))inc(ans,f[n][s][0]);
	printf("%d",ans);
}
signed main(){
	int lpx=1;
	F(____,1,lpx)solve();
}