#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <string>
#include <vector>
#include <deque>
#include <list>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cmath>
#include <cstring>
#include <cctype>
#include <sstream>
#include <set>
#include <map>
#include <queue>
#include <complex>
using namespace std;
#define REP(i,n) for(int i = 0; i < (int)n; i++)
#define FOR(i,a,b) for(int i = a; i < (int)b; i++)
const int INF = 1<<28;

int dx[] = {-1, 0, 1, 0};
int dy[] = {0, 1, 0, -1};

struct P {
	int h, w, d;
	P(int a, int b, int c) {h = a; w = b; d = c;}
	bool operator > (const P& a) const {
		return d > a.d; 
	}
};

int main() {
	int W, H;
	while(cin >> W >> H, W|H) {
		int field[H][W];
		REP(i, H) REP(j, W) {
			char in; cin >> in;
			if(in == '#') field[i][j] = 10;
			else if(in == '.') field[i][j] = 100;
			else if(in == 'X') field[i][j] = 1000;
			else if(in == 'E') field[i][j] = 2;
			else if(in == 'N') field[i][j] = 3;
			else if(in == 'W') field[i][j] = 0;
			else if(in == 'S') field[i][j] = 1;
		}

		queue<P> q;
		priority_queue<P, vector<P>, greater<P> > pq;
		REP(i, H) REP(j, W)
			if(field[i][j] < 4)
				q.push(P(i, j, field[i][j]));

		int cnt = 0;
		while(q.size() | pq.size()) {

			//dicide direction
			while(q.size()) {
				P pp = q.front(); q.pop();
				bool flg = true;
				REP(i, 4) {
					int nd = (pp.d + 3 + i) % 4;
					int nh = pp.h + dy[nd], nw = pp.w + dx[nd];
					if(0 <= nh && 0 <= nw && nh < H && nw < W  && field[nh][nw] > 99) {
						pp.d = nd; pq.push(pp);
						field[pp.h][pp.w] = nd;
						flg = false;
						break;
					}
				}
				if(flg) pq.push(pp);
			}

			//dicide move
			while(pq.size()) {
				P pp = pq.top(); pq.pop();
				int nh = pp.h + dy[pp.d], nw = pp.w + dx[pp.d];
				if(field[nh][nw] > 99) {
					if(field[nh][nw] == 1000)
						field[pp.h][pp.w] = 100;
					else {
						swap(field[pp.h][pp.w], field[nh][nw]);
						q.push(P(nh, nw, pp.d));
					}
				}
				else
					q.push(pp);
			}
			cnt++;
			if(cnt >= 180) break;
		}
		if(cnt >= 180) cout << "NA" << endl;
		else cout << cnt << endl;
	}
	return 0;
}