//interactive
#define MD 998244353
ll@n,@m;
string@s[n];
ll d[3][3]{};
rep(y,n){
	rep(x,m){
		ll c=s[y][x];
		ll v=c=='W'?0:c=='B'?1:2;
		d[(x+y)%3][v]+=1;
	}
}
Mint z0=1,z1=1;
rep(i,3){
	z0*=d[i][2]?Mint(2)**(d[i][2]-1):Mint(d[i][1]&1^0);
	z1*=d[i][2]?Mint(2)**(d[i][2]-1):Mint(d[i][1]&1^1);
}
wt(z0+z1);