#include<iostream>

#include<cstring>

using namespace std;

struct node{

    int x1;

    int y1;

    int num;

}arry[];

const int MAXN = ;

char Map[MAXN][MAXN];

int ac;

int havekey[];

int findkey[];

void check();

void dfs(int x,int y){

    if(Map[x][y] != 'X'){

        switch(Map[x][y]){

            case 'a':

            case 'b':

            case 'c':

            case 'd':

            case 'e':

                findkey[Map[x][y] - 'a']++;

                break;

            case 'A':

            case 'B':

            case 'C':

            case 'D':

            case 'E':

                arry[Map[x][y] - 'A'].x1 = x;

                arry[Map[x][y] - 'A'].y1 = y;

                arry[Map[x][y] - 'A'].num++;

                return;

            case 'G':

                ac = true;

                return;

        }

        Map[x][y] = 'X'; //标记已经走过

        dfs(x - ,y);

        dfs(x + ,y);

        dfs(x,y - );

        dfs(x,y + );

        check();

    }

}

void check(){

    for(int i = ;i < ;i++){

        if(arry[i].num){

            if(findkey[i] == havekey[i]){

                Map[arry[i].x1][arry[i].y1] = 'X';

                dfs(arry[i].x1 + ,arry[i].y1);

                dfs(arry[i].x1 - ,arry[i].y1);

                dfs(arry[i].x1,arry[i].y1 + );

                dfs(arry[i].x1,arry[i].y1 - );

            }

        }

    }

}

int main(){

    int m,n;

    while((cin >> m >> n) && (m || n)){

        memset(havekey,,sizeof(havekey));

        memset(findkey,,sizeof(findkey));

        memset(arry,,sizeof(arry));

        memset(Map,'X',sizeof(Map));//初始边界，否则递归搜索时，会越界空指针

        ac = ;

        int a1,b1;

        for(int i = ;i <= m;i++){

            for(int j = ;j <= n;j++){

                cin >> Map[i][j];

                if(Map[i][j] == 'S')

                    a1 = i,b1 = j;

                else if(Map[i][j] >= 'a' && Map[i][j] <= 'e')//将其保存至数组

                    havekey[Map[i][j] - 'a']++;

            }

        }

        dfs(a1,b1);

        if(ac){

            cout << "YES" << endl;

        }else cout << "NO" << endl;

    }

    return ;

}

//4 4

//S.X.

//a.X.

//..XG

//....

//3 4

//S.Xa

//.aXB

//b.AG

//0 0