/*
BFS:多类单个门，配多把钥匙
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#include <malloc.h>
#include <ctype.h>
#include <math.h>
#include <string>
#include <iostream>
#include <algorithm>
using namespace std;
#include<queue>
const int INF = 999999;
struct node
{
int x,y;
};
struct DOOR
{
int x,y;
int find;
};
queue<node> q;
int n,m,time;
char mp[25][25];
int vis[25][25];
int key[5];
int skey[5];
DOOR door[5];
int xx[4]={1,-1,0,0};
int yy[4]={0,0,1,-1};
int bfs(int x,int y)
{
while(!q.empty ())
q.pop ();
node from,next;
int i;
from.x=x,from.y=y;
vis[x][y]=1;
q.push (from);
while(!q.empty ())
{
from=q.front ();
q.pop ();
for(i=0;i<4;i++)
{
int dx=from.x+xx[i];
int dy=from.y+yy[i];
if(dx>=0&&dx<n&&dy>=0&&dy<m&&vis[dx][dy]==0&&mp[dx][dy]!='X')
{
next.x=dx;
next.y=dy;
if(mp[dx][dy]=='G') return 1;
else if(mp[dx][dy]>='a'&&mp[dx][dy]<='e')//find the key
{
vis[dx][dy]=1;
key[mp[dx][dy]-'a']++;
if(key[mp[dx][dy]-'a']==skey[mp[dx][dy]-'a']&&door[mp[dx][dy]-'a'].find==1)
{
door[mp[dx][dy]-'a'].find=2;
node t;
t.x=door[mp[dx][dy]-'a'].x;
t.y=door[mp[dx][dy]-'a'].y;
vis[t.x][t.y]=1;
q.push (t);
}
q.push (next);
}
else if(mp[dx][dy]>='A'&&mp[dx][dy]<='E')//find the door
{
door[mp[dx][dy]-'A'].x=dx;
door[mp[dx][dy]-'A'].y=dy;
door[mp[dx][dy]-'A'].find=1;
if(key[mp[dx][dy]-'A']==skey[mp[dx][dy]-'A']&&door[mp[dx][dy]-'A'].find==1)
{
door[mp[dx][dy]-'A'].find=2;
node t;
t.x=door[mp[dx][dy]-'A'].x;
t.y=door[mp[dx][dy]-'A'].y;
vis[t.x][t.y]=1;
q.push (t);
}
}
else
{
vis[dx][dy]=1;
q.push (next);
}
}
}
}
return 0;
}
int main()
{
int i,j;
int x,y;
while(scanf("%d%d",&n,&m)!=EOF)
{
if(n==0&&m==0) break;
memset(mp,0,sizeof(mp));
memset(vis,0,sizeof(vis));
memset(key,0,sizeof(key));
memset(skey,0,sizeof(skey));
memset(door,0,sizeof(door));
for(i=0;i<n;i++)
{
scanf("%s",mp[i]);
for(j=0;j<m;j++)
{
if(mp[i][j]=='S')
x=i,y=j;
if(mp[i][j]>='a'&&mp[i][j]<='e')
skey[mp[i][j]-'a']++;
}
}
int ans=bfs(x,y);
if(ans==1)
printf("YES\n");
else
printf("NO\n");
}
return 0;
}
/*
4 4
Saaa
aaaa
XXAX
GBbb
*/
