#include <iostream>
#include <vector>
#include <string>
using namespace std;

int foo(char c) {
	switch(c) {
		case 'N' : return 0;
		case 'E' : return 1;
		case 'S' : return 2;
		case 'W' : return 3;
	}
	return -1;
}

char bar(int n) {
	switch(n) {
		case 0 : return 'N';
		case 1 : return 'E';
		case 2 : return 'S';
		case 3 : return 'W';
	}
	return '@';
}

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

int W, H;
bool valid(int i, int j) {
	return 0 <= i && i < H && 0 <= j && j < W;
}

int main() {
	while(cin >> W >> H, W || H) {
		vector<string> sq;
		for(int i = 0; i < H; i++) {
			string s;
			cin >> s; sq.push_back(s);
		}

		int ret = -1;
		for(int t = 0; t < 180; t++) {
			vector<string> nex;

			/* turn */
			for(int i = 0; i < sq.size(); i++) {
				for(int j = 0; j  < sq[i].size(); j++) {
					if(foo(sq[i][j]) != -1) {
						for(int k = 0; k < 4; k++) {
							int x,y;
							int dir = (k + 4 - foo(sq[i][j])) % 4;
							y = i + dy[dir];
							x = j + dx[dir];
							if(!valid(y, x))
								continue;
							if(sq[y][x] == '.' || sq[y][x] == 'X') {
								sq[i][j] = bar((5 - dir)%4);
								break;
							}
						}
					}
				}
			}

			/* debug 
			if(t < 20) {
				for(int i = 0; i < sq.size(); i++) {
					for(int j = 0; j < sq[i].size(); j++) {
						cout << sq[i][j];
					} cout << endl;
				}
				cout << endl;
			}
			// */

			/* move */
			for(int i = 0; i < 4; i++) {
				/*
				if(t < 20)
					cout << bar((3-i)%4) << endl;
				// */
				for(int j = 0; j < sq.size(); j++) {
					for(int k = 0; k < sq[j].size(); k++) {
						if(sq[j][k] == bar((3-i)%4)) {
							int x, y;
							x = k + dx[(i+2)%4];
							y = j + dy[(i+2)%4];
							if(valid(y,x) && sq[y][x] == '.') {
								sq[y][x] = (int)sq[j][k] - ('A' - 'a');
								sq[j][k] = '@';
							}
							else if(valid(y,x) && sq[y][x] == 'X') {
								sq[y][x] = 'x';
								sq[j][k] = '@';
								ret = t;
							}
						}
					}
				}
			}
			/* debug 
			if(t < 20) {
				for(int i = 0; i < sq.size(); i++) {
					for(int j = 0; j < sq[i].size(); j++) {
						cout << sq[i][j];
					} cout << endl;
				}
				cout << endl;
			}
			// */

			for(int i = 0; i < sq.size(); i++) {
				for(int j = 0; j < sq[i].size(); j++) {
					if(sq[i][j] == '@')
						sq[i][j] = '.';
					else if(sq[i][j] == 'x')
						sq[i][j] = 'X';
					if(sq[i][j] == 'n' || sq[i][j] == 'e' || sq[i][j] == 'w' || sq[i][j] == 's')
						sq[i][j] = (int)sq[i][j] + 'A' - 'a';
				}
			}
		}

		for(int i = 0; i < sq.size(); i++) {
			for(int j = 0; j < sq.size(); j++) {
				if(foo(sq[i][j]) != -1) {
					ret = -1;
				}
			}
		}

		if(ret == -1)
			cout << "NA" << endl;
		else
			cout << ret + 1 << endl;
	}
}