Go: package main

import (
	"bufio"
	"os"
	"strconv"
	"strings"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

type Point struct {
	x, y int
}

func main() {
	dx := []int{1, 0, -1, 0}
	dy := []int{0, -1, 0, 1}
	maze := make([][]rune, 30)
	for i := range maze {
		maze[i] = make([]rune, 30)
	}
	next := make([][]rune, 30)
	for i := range next {
		next[i] = make([]rune, 30)
	}
	check := make([][]int, 30)
	for i := range check {
		check[i] = make([]int, 30)
	}
	for scanner.Scan() {
		buf := strings.Split(scanner.Text(), " ")
		W, _ := strconv.Atoi(buf[0])
		H, _ := strconv.Atoi(buf[1])
		if W == 0 && H == 0 {
			break
		}
		for i := 0; i < H; i++ {
			scanner.Scan()
			buf_ := scanner.Text()
			for j, v := range buf_ {
				maze[i][j] = v
			}
		}
		man := 0
		for i := 0; i < H; i++ {
			for j := 0; j < H; j++ {
				if maze[i][j] != '.' && maze[i][j] != 'X' && maze[i][j] != '#' {
					switch maze[i][j] {
					case 'E':
						maze[i][j] = 0
						man++
					case 'N':
						maze[i][j] = 1
						man++
					case 'W':
						maze[i][j] = 2
						man++
					case 'S':
						maze[i][j] = 3
						man++
					}
				}
			}
		}
		ans := -1
		for t := 0; t <= 180; t++ {
			if man == 0 {
				ans = t
				break
			}
			for i := 0; i < H; i++ {
				for j := 0; j < W; j++ {
					check[i][j] = 0x7FFFFFFF
				}
			}
			for i := 0; i < H; i++ {
				for j := 0; j < W; j++ {
					if maze[i][j] > 3 {
						continue
					}
					l := (maze[i][j] + 3) % 4
					for k := 0; k < 4; k++ {
						y := i + dy[l]
						x := j + dx[l]
						if 0 <= y && y < H && 0 <= x && x < W && (maze[y][x] == '.' || maze[y][x] == 'X') {
							maze[i][j] = l
							check[y][x] = min(check[y][x], int((l+2)%4))
							break
						}
						l = (l + 1) % 4
					}
				}
			}
			for i := 0; i < H; i++ {
				for j := 0; j < W; j++ {
					next[i][j] = maze[i][j]
				}
			}
			for i := 0; i < H; i++ {
				for j := 0; j < W; j++ {
					if maze[i][j] > 3 {
						continue
					}
					y := i + dy[maze[i][j]]
					x := j + dx[maze[i][j]]
					if 0 <= y && y < H && 0 <= x && x < W && check[y][x] == int((maze[i][j]+2)%4) {
						if maze[y][x] == '.' {
							next[y][x] = maze[i][j]
						} else if maze[y][x] == 'X' {
							man--
						}
						next[i][j] = '.'
					}
				}
			}
			for i := 0; i < H; i++ {
				for j := 0; j < W; j++ {
					maze[i][j]=next[i][j]
				}
			}
		}
		if ^ans != 0 {
			fmt.Println(ans)
		} else {
			fmt.Println("NA")
		}
	}
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
#define rep(i,n) for(int i = 0 ; i < n ; i++)

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

struct hero{
	int x,y,d;
	hero(){}
	hero(int a,int b,int c){ x = a , y = b , d = c;}
};
bool operator == (const hero a,const hero b){
	return a.d == b.d && a.x == b.x && a.y == b.y;
}
int H,W;
char data[30][30];
vector<hero> h;

int exists(int x,int y){
	if(data[y][x] == '#') return true;
	rep(i,h.size()) if(h[i].x == x && h[i].y == y) return true;
	return false;
}

int isok(int d,int x,int y){
	rep(i,h.size()){
		if(h[i].x == x && h[i].y == y && h[i].d == d){
			return i;
		}
	}
	return -1;
}
int wmove(hero he){
	rep(I,4){
		int i = (he.d + I) % 4;
		if( !exists(he.x+dx[i] , he.y + dy[i]) ) return (i+3) %4;
	}
	return he.d;
}

int check(int x,int y){
	return x < 0 || y < 0 || x >= W || y >= H;
}

int main(){
	while(cin >> W >> H , H || W){
		h.clear();
		rep(i,H)rep(j,W){
			hero tmp;
			char c; cin >> c;
			if(c == 'N' || c == 'W' || c == 'S' || c == 'E'){
				if(c=='N') tmp.d = 0;
				if(c=='W')tmp.d = 1;
				if(c=='S')tmp.d = 2;
				if(c=='E')tmp.d = 3;
				tmp.x = j , tmp.y = i;
				h.push_back(tmp);
			}
			data[i][j] = c;

		}
		rep(T,181){
			//cout << h[0].x << " " << h[0].y << " " << h[0].d << " " << endl;
			if(h.size() == 0){ cout << T << endl; goto exit;}
			rep(i,h.size()) h[i].d = wmove(h[i]);
			vector<hero> next = h;
			//rep(i,h.size()) cout << i << ":" << h[i].x <<"," << h[i].y << "=" << h[i].d << endl;
			rep(i,H)rep(j,W){
				rep(d,4){
					if(data[i][j] == '#' || check(j+dx[d],i+dy[d])) continue;
					int r = isok( (d+1)%4 , j+dx[d] , i+dy[d] );
					//if(i == 1 && j == 2) cout << r << "=" << (d+3)%4 << endl;
					if(~r){
						next[r].x = j ;
						next[r].y = i ;
						break;
					}
				}
			}
			rep(i,next.size()){
				if(data[next[i].y][next[i].x] == 'X'){
					next[i] = hero(-1,-1,-1);
				}
			}
			next.erase(remove(next.begin(),next.end(),hero(-1,-1,-1)),next.end());
			h = next;
		}
		cout << "NA" << endl;
		exit:;
	}
}

C++: #include<cstdio>
#include<cstdlib>
#include<ctime>
#include<cmath>
#include<cstring>
#include<cctype>
#include<complex>
#include<iostream>
#include<sstream>
#include<algorithm>
#include<functional>
#include<vector>
#include<string>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<bitset>
using namespace std;

const int dx[] = {1,0,-1,0};
const int dy[] = {0,-1,0,1};
#define INF 1e+8
#define EPS 1e-10
#define PB push_back
#define fi first
#define se second
#define ll long long 
#define reps(i,j,k) for(int i = (j); i < (k); i++)
#define rep(i,j) reps(i,0,j)
typedef pair<int,int> Pii;
typedef vector<int> vi;
class Data{
	public:
	int y;
	int x;
	int type;
	Data(){}
	Data(int _y,int _x,int _type){
		y = _y;
		x = _x;
		type = _type;
	}
	bool operator==(const Data &a)const{
		return (y == a.y && x == a.x);
	}
};
int chenge(char info){
	if(info == 'E')return 0;
	if(info == 'N')return 1;
	if(info == 'W')return 2;
	if(info == 'S')return 3;
}
bool check(char info){
	if(info != '#' && info != 'X' && info != '.')return true;
	return false;
}
int main(){
	int w,h;
	while(scanf("%d%d",&w,&h),w){
		char stage[32][32]={{0}};
		vector < Data > player;
		rep(i,h){
			scanf("%s",stage[i]);
			rep(j,w){
				if(check(stage[i][j])){
					player.PB(Data(i,j,chenge(stage[i][j])));
				}
			}
		}

		int cnt = 0;
		while(player.size() > 0){
			/*
			rep(i,h){
				printf("%s\n",stage[i]);
			}
			printf("type:%d\n",player[0].type);
			puts("-------------------");
			*/
			cnt++;
			if(cnt > 180){
				cnt = -1;
				break;
			}
			int len = player.size();
			bool next[32][32]={{false}};
			int from[32][32]={{0}};
			vector < Data > memo;
			vector < Data > del;
			rep(i,len){
				Data d = player[i];
				rep(j,4){
					int k = (d.type+j+3)%4;
					int nx = d.x + dx[k];
					int ny = d.y + dy[k];
					if(ny < 0 || ny > h-1 || nx < 0 || nx > w-1)continue;
					if(stage[ny][nx] == '.' || stage[ny][nx] == 'X'){
						memo.PB(Data(ny,nx,k));
						next[ny][nx] = true;
						from[d.y][d.x] = i+1;
						break;
					}
				}
			}
			rep(i,memo.size()){
				if(!next[memo[i].y][memo[i].x]){
					player[i].type = memo[i].type;
					continue;
				}
				int cnt = 0;
				rep(j,4){
					int ny = memo[i].y+dy[j];
					int nx = memo[i].x+dx[j];
					if(ny < 0 || ny > h-1 || nx < 0 || nx > w-1)continue;
					if(check(stage[ny][nx]) && from[ny][nx] == i+1){
						stage[ny][nx] = '.';
						if(stage[memo[i].y][memo[i].x] == 'X'){
							del.PB(Data(ny,nx,memo[i].type));
						}
						else{
							player[i].y = memo[i].y;
							player[i].x = memo[i].x;
							player[i].type = memo[i].type;
							stage[player[i].y][player[i].x] = memo[i].type+48;
						}
						next[memo[i].y][memo[i].x] = false;
						break;
					}
				}
			}
			rep(i,del.size()){
				vector<Data>::iterator it = remove(player.begin(),player.end(),del[i]);
				player.erase(it,player.end());
			}
		}
		if(cnt == -1)puts("NA");
		else printf("%d\n",cnt);
	}
	return 0;
}