ll n,m;
bool board[3000][3000];
int parent[3000][3000];
pl a;
queue<pl> q;
ll visited[3000][3000], visited1[3000][3000];
void reconstruct_path(ll x, ll y){
	string path="";
      // cout<<"HERE"<<'\n';
   // exit(0);
	while(make_pair(x, y)!=a){
       // dbg(x, y);
		if(parent[x][y]==1){
			//we went right so go left
			path+='R';
			y--;
		}
		else if(parent[x][y]==2){
			path+='L';
			y++;
		}
		else if(parent[x][y]==3){
			x++;
			path+='U';
		}
		else if(parent[x][y]==4){
			x--;
			path+='D';
		}
	}
    reverse(all(path));
	cout<<int(path.size())<<"\n"<<path<<'\n';
}
int main(){setIO("");
    re(n, m);
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            visited[i][j]=visited1[i][j]=1e9+7;
            char c;
            re(c);
            if(c=='#'){
                board[i][j]=0;
            }
            if(c=='A'){
                a={i, j};
                visited[i][j]=0;
                board[i][j]=1;
            }
            if(c=='.'){
                board[i][j]=1;
            }
            if(c=='M'){
                visited1[i][j]=0;
                q.push({i, j});
                board[i][j]=1;
            }
        }
    }
    //multisource bfs
    while(q.size()){
        ll x=q.front().f, y=q.front().s;q.pop();
       // dbg(x, y);
        int dx[]={1, -1, 0, 0};
        int dy[]={0, 0, 1, -1};
        for(int i=0;i<4;i++){
            ll x1=x+dx[i], y1=y+dy[i];
            if(x1>=1 and x1<=n and y1>=1 and y1<=m and board[x1][y1] and visited1[x][y]+1<=visited1[x1][y1]){
                visited1[x1][y1]=1+visited1[x][y];
                q.push({x1, y1});
            }
        }
    }
    q=queue<pl>();
    q.push(a);
    while(q.size()){
        ll x=q.front().f, y=q.front().s;
       // dbg(x, y);
		q.pop();
        if(x==1 or x==n or y==1 or y==m){
			cout<<"YES"<<'\n';
			reconstruct_path(x, y);
			return 0;
        }
        else{
            int dx[]={1, -1, 0, 0};
            int dy[]={0, 0, 1, -1};
            for(int i=0;i<4;i++){
                ll x1=x+dx[i], y1=y+dy[i];
                if(x1>=1 and x1<=n and y1>=1 and y1<=m and board[x1][y1] and 1+visited[x][y]<visited1[x1][y1] and 1+visited[x][y]<=visited[x1][y1]){
					visited[x1][y1]=1+visited[x][y];
					q.push({x1, y1});
					//1 for going right
					//2 for left
					//3 for up
					//4 fur down
                    if(dx[i]==1 and dy[i]==0){
                    //go down
                    	parent[x1][y1]=4;
					}
					if(dx[i]==0 and dy[i]==1){
						//right
						parent[x1][y1]=1;
					}
					if(dx[i]==-1 and dy[i]==0){
						//up
						parent[x1][y1]=3;
					}
					else if(dx[i]==0 and dy[i]==-1){
						parent[x1][y1]=2;
					}
                }
            }
        }
    }
	cout<<"NO"<<'\n';
}