#include <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second

template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pll> pip;
const ll INF = 1ll<<29;
const ll MOD = 1000000007;
const double EPS  = 1e-9;

int dx[4] = {1,0,-1,0}, dy[4] = {0,1,0,-1};
int dd[4] = {1,0,3,2}; // ???, ???, ???, ???

int W, H;
int maps[30][30];
bool wait[30][30][4]; // (i,j)???k??????????????????

int main() {
	while (cin >> W >> H, W || H) {
		queue<pii> que;
		
		REP(i, H) {
			string str; cin >> str;
			
			REP(j, W) {
				int num;
				switch (str[j]) {
					case '#': num = -1; break;
					case '.': num = -2; break;
					case 'X': num = -3; break;
					
					case 'E': num = 0; break;
					case 'S': num = 1; break;
					case 'W': num = 2; break;
					case 'N': num = 3; break;
				}
				maps[i][j] = num;
				if (num >= 0) que.push(pii(i, j));
			}
		}
		
		int turn = 0;
		
		while (turn <= 180 && !que.empty()) {
			//puts(""); REP(i, H) {REP(j, W) printf("%3d", maps[i][j]); puts("");}
			
			for (int i = que.size() - 1; i >= 0; i--) {
				pii now = que.front(); que.pop();
				int y = now.fi, x = now.se;
				int d = maps[y][x];
				
				int nextd = -1;
				
				REP(i, 4) {
					int nd = (d + dd[i]) % 4;
					int xx = x + dx[nd], yy = y + dy[nd];
					if (!(xx >= 0 && xx < W && yy >= 0 && yy < H)) continue;
					if (maps[yy][xx] < 0 && maps[yy][xx] != -1) {
						wait[yy][xx][(nd + 2) % 4] = true;
						nextd = nd;
						
						//printf("%d %d -> %d %d (%d)\n", y, x, yy, xx, nd);
						break;
					}
				}
				
				if (nextd == -1) que.push(pii(y, x));
			}
			
			REP(i, H) REP(j, W) {
				bool ok = false;
				REP(k, 4) {
					int d = dd[(k + 1) % 4];
					if (!wait[i][j][d]) continue;
					int y = i + dy[d], x = j + dx[d];
					maps[y][x] = (d + 2) % 4;
					
					if (ok) que.push(pii(y, x));
					else {
						if (maps[i][j] != -3) {
							swap(maps[y][x], maps[i][j]);
							que.push(pii(i, j));
						}
						else maps[y][x] = -2;
						ok = true;
					}
					wait[i][j][d] = false;
				}
				
			}
			
			turn++;
		}
		
		if (turn > 180) puts("NA");
		else cout << turn << endl;
	}
	return 0;
}