// g++ -std=c++11 a.cpp
#include<iostream>
#include<vector>
#include<string>
#include<algorithm>	
#include<map>
#include<set>
#include<unordered_map>
#include<utility>
#include<cmath>
#include<random>
#include<cstring>
#include<queue>
#include<stack>
#include<bitset>
#include<cstdio>
#include<sstream>
#include<iomanip>
#include<assert.h>
#include<typeinfo>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define FOR(i,a) for(auto i:a)
#define pb push_back
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)
#define show1d(v) rep(i,v.size())cout<<" "<<v[i];cout<<endl<<endl;
#define show2d(v) rep(i,v.size()){rep(j,v[i].size())cout<<" "<<v[i][j];cout<<endl;}cout<<endl;
using namespace std;
//kaewasuretyuui
typedef long long ll;
#define int ll
typedef int Def;
typedef pair<Def,Def> pii;
typedef vector<Def> vi;
typedef vector<vi> vvi;
typedef vector<pii> vp;
typedef vector<vp> vvp;
typedef vector<string> vs;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef pair<Def,pii> pip;
typedef vector<pip>vip;
#define mt make_tuple
typedef tuple<int,int,int,int> tp;
typedef vector<tp> vt;
template<typename A,typename B>bool cmin(A &a,const B &b){return a>b?(a=b,true):false;}
template<typename A,typename B>bool cmax(A &a,const B &b){return a<b?(a=b,true):false;}
//template<class C>constexpr int size(const C &c){return (int)c.size();}
//template<class T,size_t N> constexpr int size(const T (&xs)[N])noexcept{return (int)N;}
const double PI=acos(-1);
const double EPS=1e-9;
Def inf = sizeof(Def) == sizeof(long long) ? 2e18 : 1e9+10;
int dx[]={0,1,0,-1};
int dy[]={1,0,-1,0};//RDLU

int d[1010][1010][4];
signed main(){
	int n,m,q;
	while(cin>>n>>m>>q,n){
		string s;
		cin>>s;
		vs in(n);
		rep(i,n)cin>>in[i];
		int sx,sy,gx,gy;
		rep(i,n)rep(j,m)if(in[i][j]=='S'){
			sx=i,sy=j;
		}else if(in[i][j]=='G'){
			gx=i,gy=j;
		}
		vvi ne(s.size()+1,vi(4,inf));
		for(int i=s.size()-1;i>=0;i--){
			int t=1;
			if(s[i]=='R')t=-1;
			rep(j,4)ne[i][j]=ne[i+1][(j+4+t)%4];
			if(s[i]=='R')ne[i][1]=i+1;
			if(s[i]=='L')ne[i][3]=i+1;
		}
		// show2d(ne);
		
		rep(i,1010)rep(j,1010)rep(k,4)
			d[i][j][k]=inf;
		d[sx][sy][3]=0;
		priority_queue<tp>q;
		q.push(tp(0,sx,sy,3));
		while(!q.empty()){
			Def cost,x,y,to;
			tie(cost,x,y,to)=q.top();
			cost*=-1;
			q.pop();
			if(cost>d[x][y][to])continue;
			rep(k,4){
				int nx=x+dx[k];
				int ny=y+dy[k];
				if(nx<0||ny<0||nx>=n||ny>=m)continue;
				if(in[nx][ny]=='#')continue;
				int nto=k;
				int ncost=ne[cost][(k-to+4)%4];
				if(k==to)ncost=cost;
				if(ncost==inf)continue;
				if(ncost<d[nx][ny][nto]){
					d[nx][ny][nto]=ncost;
					q.push(tp(-ncost,nx,ny,nto));
				}
			}
		}
		rep(i,4)if(d[gx][gy][i]-inf){
			cout<<"Yes"<<endl;
			goto end;
		}
		cout<<"No"<<endl;
		end:;
	}
}






