#include<bits/stdc++.h>
#define int long long
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define per(i,a,b) for(int i=(a);i>=(b);i--)
#define fi first
#define se second
#define eb emplace_back
#define popc __builtin_popcount
#define clz __builtin_clz
#define ctz __builtin_ctz
#define sgn(x) ((x)&1?-1:1)
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<pii> vp;
typedef unsigned long long ull;
typedef long double ld;

int read() {
    int x=0,w=1; char c=getchar(); 
    while(!isdigit(c)) {if(c=='-') w=-1; c=getchar();}
    while(isdigit(c)) {x=x*10+c-'0'; c=getchar();}
    return x*w;
}

const int N=1e6+9,mod=998244353,inv2=(mod+1)/2;
int n,ca,cb,f[N];
char s[N];

signed main() {
    int T=read();
    while(T--) {
        scanf("%lld%s",&n,s+1);
        f[1]=1; int ca=(s[1]=='W'), cb=(s[1]=='B');
        rep(i,2,2*n) {
            if(ca==cb) f[i]=f[i-1];
            else if(s[i]=='W'&&ca>cb) f[i]=f[i-1];
            else if(s[i]=='B'&&ca<cb) f[i]=f[i-1];
            else if(s[i]=='W'&&ca+1==cb) f[i]=f[i-1]*2%mod;
            else if(s[i]=='B'&&cb+1==ca) f[i]=f[i-1]*2%mod;
            else if(s[i]=='W') f[i]=f[i-1]*(cb-ca)*(cb-ca-1)%mod;
            else if(s[i]=='B') f[i]=f[i-1]*(ca-cb)*(ca-cb-1)%mod;
            ca+=(s[i]=='W'), cb+=(s[i]=='B');
        }
        printf("%lld\n",f[2*n]*inv2%mod*inv2%mod);
    }
    return 0;
}