#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
#include<map>
#include<set>
#include<utility>
#include<cmath>
#include<cstring>
#include<queue>
#include<cstdio>
#include<sstream>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define mp make_pair
#define all(in) in.begin(),in.end()
const double PI=acos(-1);
const double EPS=1e-8;
const int inf=1e9;
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
int main(){
	int dx[]={0,-1,0,1,0,-1,0,1};
	int dy[]={1,0,-1,0,1,0,-1,0};
	int n,m;
	while(cin>>m>>n,n+m){
		vector<string>in(n);
		rep(i,n)cin>>in[i];
		rep(i,n)rep(j,m)if(in[i][j]=='N')in[i][j]='0';
		else if(in[i][j]=='E')in[i][j]='3';
		else if(in[i][j]=='S')in[i][j]='2';
		else if(in[i][j]=='W')in[i][j]='1';
		int c=0;
		rep(i,n)rep(j,m)if(isdigit(in[i][j]))c++;
		rep(q,181){
			if(q==180){
				cout<<"NA"<<endl;
				break;
			}
			vector<string>tmp=in;
			rep(i,n)rep(j,m)if(isdigit(tmp[i][j]))tmp[i][j]='.';
			rep(i,n)for(int j=m-1;j>=0;j--)if(isdigit(in[i][j])){
				int t=in[i][j]-'0';
				rep(k,4)if(in[i+dx[t+k]][j+dy[t+k]]!='#'&&
					!isdigit(in[i+dx[t+k]][j+dy[t+k]])){
					//if(!isdigit(tmp[i+dx[t+k]][j+dy[t+k]]))
					if(in[i+dx[t+k]][j+dy[t+k]]=='X'){
						c--;
						if(c==0){
							cout<<q+1<<endl;
							goto end;
						}
					}else if(!isdigit(tmp[i+dx[t+k]][j+dy[t+k]]))
						tmp[i+dx[t+k]][j+dy[t+k]]=(in[i][j]-'0'+k+3)%4+'0';
					else tmp[i][j]=in[i][j];
					break;
				}
			}
			in=tmp;
//			rep(i,n)cout<<in[i]<<endl;cout<<endl;
		}
		end:;
	}
}