#include<bits/stdc++.h>
#define rep(i,j,k) for(int i=j;i<=k;i++)
#define repp(i,j,k) for(int i=j;i>=k;i--)
#define ls(x) (x<<1)
#define rs(x) ((x<<1)|1)
#define mp make_pair
#define sec second
#define fir first
#define pii pair<int,int>
#define lowbit(i) i&-i
#define int long long
#define double long double
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const int N=305,M=6,S=(1<<15)+5,inf=(ll)8e18+7,mo=998244353;
const double eps=1e-8;
void read(int &p){
	int x=0,w=1;
	char ch=0;
	while(!isdigit(ch)){
		if(ch=='-')w=-1;
		ch=getchar();
	}
	while(isdigit(ch)){
		x=(x<<1)+(x<<3)+ch-'0';
		ch=getchar();
	}
	p=x*w;
}
int n,m,c[N][N],a[N],f[2][N][N][2],jc[N];
char s[N*2];
signed main(){
    c[0][0]=1,jc[0]=1;
    rep(i,1,300){
        c[i][0]=1;
        rep(j,1,i)
            c[i][j]=(c[i-1][j]+c[i-1][j-1])%mo;
        jc[i]=jc[i-1]*i%mo;
    }
    read(n),read(m);
    scanf("%s",s+1);
    rep(i,1,m)
        read(a[i]);
    f[0][m][0][0]=1;
    int x=0,y=0;
    rep(i,1,n+m){
        int nwi=i&1;
        rep(j,0,m){
            rep(k,0,m){
                rep(t,0,1)
                    f[nwi][j][k][t]=0;
            }
        }
        rep(j,0,m){
            rep(k,0,m){
                rep(t,0,1){
                    if(s[i]=='+'){
                        //+非A
                        f[nwi][j][k][t]+=f[nwi^1][j][k][t]*max(0ll,n-a[j]-(m-j)-(x-y-k))%mo;
                        f[nwi][j][k][t]%=mo;
                        //+非Aj
                        f[nwi][j][k+1][t]+=f[nwi^1][j][k][t];
                        f[nwi][j][k+1][t]%=mo;
                    }
                    else{
                        if(k==1&&t==1){
                            rep(p,0,j-1){
                                if(y-(m-j)>=0)f[nwi][p][0][0]+=f[nwi^1][j][1][1]*c[y-(m-j)][j-p-1]%mo*jc[j-p-1]%mo;
                                f[nwi][p][0][0]%=mo;
                            }
                        }
                        else if(k)f[nwi][j][k-1][t]+=f[nwi^1][j][k][t],f[nwi][j][k-1][t]%=mo;
                    }
                }//+Aj
                if(s[i]=='+')f[nwi][j][k+1][1]+=f[nwi^1][j][k][0],f[nwi][j][k+1][1]%=mo;
            }
        }
        if(s[i]=='+')x++;
        else y++;
    }
    printf("%lld\n",f[(n+m)&1][0][0][0]);
    return 0;
}