#include<bits/stdc++.h>
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Rep(i,a,b) for(int i=(a);i>=(b);--i)
#define ull unsigned long long
using namespace std;
inline int read()
{
	char c=getchar();int x=0;bool f=0;
	for(;!isdigit(c);c=getchar())f^=!(c^45);
	for(;isdigit(c);c=getchar())x=(x<<1)+(x<<3)+(c^48);
	if(f)x=-x;return x;
}
 
#define mod 998244353
struct modint{
	int x;
	modint(int o=0){x=o;}
	modint &operator = (int o){return x=o,*this;}
	modint &operator +=(modint o){return x=x+o.x>=mod?x+o.x-mod:x+o.x,*this;}
	modint &operator -=(modint o){return x=x-o.x<0?x-o.x+mod:x-o.x,*this;}
	modint &operator *=(modint o){return x=1ll*x*o.x%mod,*this;}
	modint &operator ^=(int b){
		modint a=*this,c=1;
		for(;b;b>>=1,a*=a)if(b&1)c*=a;
		return x=c.x,*this;
	}
	modint &operator /=(modint o){return *this *=o^=mod-2;}
	friend modint operator +(modint a,modint b){return a+=b;}
	friend modint operator -(modint a,modint b){return a-=b;}
	friend modint operator *(modint a,modint b){return a*=b;}
	friend modint operator /(modint a,modint b){return a/=b;}
	friend modint operator ^(modint a,int b){return a^=b;}
	friend bool operator ==(modint a,int b){return a.x==b;}
	friend bool operator !=(modint a,int b){return a.x!=b;}
	bool operator ! () {return !x;}
	modint operator - () {return x?mod-x:0;}
	bool operator <(const modint&b)const{return x<b.x;}
};
inline modint qpow(modint x,int y){return x^y;}

vector<modint> fac,ifac,iv;
inline void initC(int n)
{
	if(iv.empty())fac=ifac=iv=vector<modint>(2,1);
	int m=iv.size(); ++n;
	if(m>=n)return;
	iv.resize(n),fac.resize(n),ifac.resize(n);
	For(i,m,n-1){
		iv[i]=iv[mod%i]*(mod-mod/i);
		fac[i]=fac[i-1]*i,ifac[i]=ifac[i-1]*iv[i];
	}
}
inline modint C(int n,int m){
	if(m<0||n<m)return 0;
	return initC(n),fac[n]*ifac[m]*ifac[n-m];
}
inline modint sign(int n){return (n&1)?(mod-1):(1);}

#define fi first
#define se second
#define pb push_back
#define mkp make_pair
typedef pair<int,int>pii;
typedef vector<int>vi;

#define poly vector<modint>
const modint G=3,Ginv=modint(1)/3;
inline poly one(){poly a;a.push_back(1);return a;}
vector<int>rev;
int rts[2100000];
inline int ext(int n){
	int k=0;
	while((1<<k)<n)++k;return k; 
}
inline void init(int k){
	int n=1<<k;
	rts[0]=1,rts[1<<k]=qpow(31,1<<(21-k)).x;
	Rep(i,k,1)rts[1<<(i-1)]=1ull*rts[1<<i]*rts[1<<i]%mod;
	For(i,1,n-1)rts[i]=1ull*rts[i&(i-1)]*rts[i&-i]%mod;
}

void ntt(poly&a,int k,int typ){
	int n=1<<k;
	static ull tmp[2100000];
	for(int i=0;i<n;++i)tmp[i]=a[i].x;
	if(typ==1){
		for(int l=n>>1;l>=1;l>>=1){
			ull*k=tmp;
			for(int*g=rts;k<tmp+n;k+=(l<<1),++g){
				for(ull*x=k;x<k+l;++x){
					int o=x[l]%mod*(*g)%mod;
					x[l]=*x+mod-o,*x+=o;
				}
			}
		}
		for(int i=0;i<n;++i)a[i].x=tmp[i]%mod;
	}else{
		for(int l=1;l<n;l<<=1){
			ull*k=tmp;
			for(int*g=rts;k<tmp+n;k+=(l<<1),++g){
				for(ull*x=k;x<k+l;++x){
					int o=x[l]%mod;
					x[l]=(*x+mod-o)*(*g)%mod,*x+=o;
				}
			}
		}
		int iv=qpow(n,mod-2).x;
		for(int i=0;i<n;++i)a[i].x=tmp[i]%mod*iv%mod;
		reverse(a.begin()+1,a.end());
	}
}
 
poly operator +(poly a,poly b){
	int n=max(a.size(),b.size());a.resize(n),b.resize(n);
	For(i,0,n-1)a[i]+=b[i];return a;
}
poly operator -(poly a,poly b){
	int n=max(a.size(),b.size());a.resize(n),b.resize(n);
	For(i,0,n-1)a[i]-=b[i];return a;
}
poly operator *(poly a,modint b){
	int n=a.size();
	For(i,0,n-1)a[i]*=b;return a;
} 
poly operator *(poly a,poly b){
	if(!a.size()||!b.size())return {};
	if((int)a.size()<=32 || (int)b.size()<=32){
		poly c(a.size()+b.size()-1,0);
		for(int i=0;i<a.size();++i)for(int j=0;j<b.size();++j)c[i+j]+=a[i]*b[j];
		return c; 
	}
	int n=(int)a.size()+(int)b.size()-1,k=ext(n);
	a.resize(1<<k),b.resize(1<<k);
	ntt(a,k,1),ntt(b,k,1);
	For(i,0,(1<<k)-1)a[i]*=b[i];
	ntt(a,k,-1),a.resize(n);return a;
}

poly Tmp;
poly pmul(poly a,poly b,int n,bool ok=0)
{
	int k=ext(n);
	a.resize(1<<k),ntt(a,k,1);
	if(!ok) b.resize(1<<k),ntt(b,k,1),Tmp=b;
	For(i,0,(1<<k)-1)a[i]*=Tmp[i];
	ntt(a,k,-1),a.resize(n);
	return a;
}

#define maxn 200005
#define inf 0x3f3f3f3f

int n;
int s[maxn][2],p[maxn][2];

struct mat{
	poly f[2][2];
	void resize(int n){For(i,0,1)For(j,0,1)f[i][j].resize(n);}
	void print(){
		For(i,0,1)For(j,0,1){
			for(auto x:f[i][j])cout<<x.x<<" ";
			cout<<"\n";
		}
	}
};
mat operator *(mat a,mat b){
	mat c;
	int mx=0;
	For(i,0,1)For(k,0,1)For(j,0,1)mx=max(mx,(int)a.f[i][k].size()+(int)b.f[k][j].size()-1);
	if(mx<32){
		For(i,0,1)For(j,0,1)For(k,0,1)c.f[i][j]=c.f[i][j]+a.f[i][k]*b.f[k][j];
		return c;
	}
	int k=ext(mx); init(k);
	For(i,0,1)For(j,0,1){
		a.f[i][j].resize(1<<k),b.f[i][j].resize(1<<k),c.f[i][j].resize(1<<k);
		ntt(a.f[i][j],k,1),ntt(b.f[i][j],k,1);
	}
	For(x,0,1)For(y,0,1)For(z,0,1)
		For(i,0,(1<<k)-1)c.f[x][y][i]+=a.f[x][z][i]*b.f[z][y][i];
	For(i,0,1)For(j,0,1){
		ntt(c.f[i][j],k,-1),c.f[i][j].resize(mx);
		while(c.f[i][j].size()>1&&!c.f[i][j].back().x)c.f[i][j].pop_back();
	}
	return c;
}

mat t[maxn];
mat solve(int l,int r){
	if(l==r)return t[l];
	int mid=l+r>>1;
	return solve(l,mid)*solve(mid+1,r);
}

signed main()
{
	
	n=read();
	string ops;
	cin>>ops;
	// arc-poi-arc-poi
	For(i,1,n){
		s[i][0]=(ops[(i-1)*2]=='Y'||ops[(i-1)*2]=='?');
		s[i][1]=(ops[(i-1)*2]=='P'||ops[(i-1)*2]=='?');
		p[i][0]=(ops[i*2-1]=='B'||ops[i*2-1]=='?');
		p[i][1]=(ops[i*2-1]=='R'||ops[i*2-1]=='?');
	}
		For(i,1,n){
			int v=i+1; if(v>n)v=1;
			For(j,0,1){
				if(s[v][j]){
					t[i].f[j][j]={0,p[i][0]+p[i][1]};
					t[i].f[!j][j]={p[i][1]&&(!j),p[i][0],p[i][1]&&(j)};
				}
			}
		}
	mat res=solve(1,n);
//	for(auto x:res.f[0][0])cout<<x.x<<" ";cout<<"\n";
//	for(auto x:res.f[1][1])cout<<x.x<<" ";cout<<"\n";
	poly qwq=res.f[0][0]+res.f[1][1];
	qwq.resize(n+1);
	cout<<qwq[n].x;
	return 0;
}