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>
#define pb push_back
#include<vector>
#include<map>
#define MAX 35
using namespace std;
int h,w;
int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
typedef pair<int,int> P;
/*
 1
2 0
 3
*/
int main(){
	map<char,int> mp;
	mp['E']=0;
	mp['N']=1;
	mp['W']=2;
	mp['S']=3;
	map<int,char> mp2;
	mp2[0]='E';
	mp2[1]='N';
	mp2[2]='W';
	mp2[3]='S';
	
	while(cin>>w>>h,w||h){
	char s[MAX][MAX];
	for(int i=0;i<h;i++){
		cin>>s[i];
	}
	vector<P> vp;
	int now=0;
	for(int i=0;i<h;i++)
	for(int j=0;j<w;j++)
	if(s[i][j]=='E'||s[i][j]=='N'||s[i][j]=='W'||s[i][j]=='S'){
		vp.pb(P(i,j));
	//	cout<<s[i][j]<<endl;
	}
	//cout<<"  "<<vp.size()<<endl;
	int cnt=0;
	int x,y;
	//cout<<vp.size()<<endl;
	while(cnt<=180&&now<vp.size()){
		cnt++;
		map<P,int> pi;
		map<int,int> ii;
		//for(int k=0;k<4;k++){
			for(int i=0;i<vp.size();i++){
				P n=vp[i];
				y=n.first;
				x=n.second;
				pi[P(y,x)]++;
			}
			for(int i=0;i<vp.size();i++){
				P n=vp[i];
				y=n.first;
				x=n.second;
				//if(ii[i]||pi[P(y,x)])
				//	continue;
				
				pi[P(y,x)]++;
				if(x==100)
					continue;
				int q=mp[s[y][x]];
				for(int j=0;j<4;j++){
					
					/*if((j+3+q)%4!=k)
						continue;
					*/
					int nx=dx[(j+3+q)%4]+x,ny=dy[(j+3+q)%4]+y;
				//	cout<<(j+3+q)%4<<endl;
					if(pi[P(ny,nx)])
						continue;
					
					
					
					if(nx>=0&&nx<w&&ny<h&&ny>=0){
						 if(s[ny][nx]=='#')
							continue;
						if(s[ny][nx]=='X'){
							vp[i]=P(100,100);
							now++;
							s[y][x]='.';
							break;
						}else if(s[ny][nx]=='.'){
							//ii[i]++;
							s[y][x]='.';
							s[ny][nx]=mp2[(j+3+q)%4];
							vp[i]=P(ny,nx);
							//pi[P(ny,nx)]++;
							break;
						}
						else if(s[ny][nx]!='#'){
							if((j+3+q)%4<mp2[s[ny][nx]]){
								char c=s[ny][nx];
								ii[i]++;
								s[y][x]='.';
								s[ny][nx]=mp2[(j+3+q)%4];
								int l=mp2[c];
								vp[i]=P(ny=dy[(l+2)%4]+ny,dx[(l+2)%4]+nx);
								s[ny=dy[(l+2)%4]+ny][dx[(l+2)%4]+nx]=c;
								//i--;
								break;
							}else{
								s[y][x]=mp2[(j+3+q)%4];
								break;
								
							}
						}
					}
				}
			}
		//}
		pi.clear();
		ii.clear();
		/*for(int i=0;i<h;i++){
		for(int j=0;j<w;j++)
			cout<<s[i][j];
			cout<<endl;
		}*/
	}
	if(now&&cnt<=180)
	cout<<cnt<<endl;
	else
	cout<<"NA"<<endl;
	}
	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#define REP(i,s,n) for(int i=s;i<n;i++)
#define rep(i,n) REP(i,0,n)
#define inf (1<<28)
#define MAX 35
#define next(a,b) ((((a+3)%4)+b)%4)
using namespace std;

struct P
{
  int x,y,dir;
  P(int x=inf,int y=inf,int dir=inf):x(x),y(y),dir(dir){}
};

int dx[] = {+1,+0,-1,+0};
int dy[] = {+0,-1,+0,+1};
int H,W;
char G[MAX][MAX];
int  D[MAX][MAX];
string DIR = "ENWS";
vector<P> vec;

bool Finish()
{
  rep(i,vec.size())if(G[vec[i].y][vec[i].x] != 'X')return false;
  return true;
}

void print()
{
  cout << "print- ---" << endl;
  rep(i,H)
    {
      rep(j,W)
	{
	  cout << G[i][j];
	}
      cout << endl;
    }
  cout << endl;
}

void decide()
{
  rep(i,vec.size())
    {
      int x = vec[i].x, y = vec[i].y, dir = vec[i].dir;
      if(G[y][x] == 'X')continue;

      rep(j,4)
	{
	  int nx = x + dx[next(dir,j)];
	  int ny = y + dy[next(dir,j)];
	  if(!(0 <= nx && nx < W && 0 <= ny && ny < H))continue;
	  if(!(G[ny][nx] == '.' || G[ny][nx] == 'X'))continue;
	  vec[i].dir = next(dir,j);
	  D[ny][nx]++;
	  break;
	}
    }
}

bool check(int x,int y,int cx,int cy)
{
  rep(i,4)
    {
      int nx = cx + dx[i];
      int ny = cy + dy[i];
      if(!(0 <= nx && nx < W && 0 <= ny && ny < H))continue;
      if(G[ny][nx] == '.' || G[ny][nx] == 'X' || G[ny][nx] == '#')continue;
      return nx == x && ny == y;
    }
}

void move()
{
  rep(i,vec.size())
    {
      int x = vec[i].x;
      int y = vec[i].y;
      if(G[y][x] == 'X')continue;

      int dir = vec[i].dir;
      int nx = x + dx[dir];
      int ny = y + dy[dir];
      if(!(0 <= nx && nx < W && 0 <= ny && ny < H))continue;
      if(!(G[ny][nx] == '.' || G[ny][nx] == 'X'))continue;
      if(D[ny][nx] == 0)continue;
      if(D[ny][nx] == 1 || (D[ny][nx] >= 2 && check(x,y,nx,ny)))
	{
	  D[ny][nx] = 0;
	  G[y][x] = '.';
	  vec[i].x = nx, vec[i].y = ny;
	  if(G[ny][nx] != 'X')G[ny][nx] = DIR[dir];
	}

    }
  rep(i,H)rep(j,W)D[i][j] = 0;
}

int main()
{
  while(cin >> W >> H,W|H)
    {
      vec.clear();
      rep(i,H)rep(j,W)
	{
	  cin >> G[i][j];
	  if(!(G[i][j] == '.' || G[i][j] == '#' || G[i][j] == 'X'))
	    {
	      char c = G[i][j];
	      int dir = (c=='E'?0:(c=='N'?1:(c=='W'?2:(c=='S'?3:-inf))));
	      vec.push_back(P(j,i,dir));
	    }
	}

      if(vec.empty())
	{
	  cout << 0 << endl;
	  continue;
	}

      rep(phase,180)
	{
	  decide();

	  move();

	  if( Finish() )
	    {
	      cout << phase+1 << endl;
	      goto Fin;
	    }
	}
      cout << "NA" << endl;
    Fin:;
    }

  return 0;
}