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 <map>
#include <cstdlib>
#include <algorithm>
#include <string>

using namespace std;

int h, w;

char data[30][30];
char next[30][30];
int dy[] = {0, -1, 0, 1};
int dx[] = {1, 0, -1, 0};
map<char, int> ctoi;
string itoc = "ENWS";

void copy(){
   for(int i=0;i<h;++i){
      for(int j=0;j<w;++j){
         data[i][j] = next[i][j];
      }
   }
}

main(){
   ctoi['E'] = 0;
   ctoi['N'] = 1;
   ctoi['W'] = 2;
   ctoi['S'] = 3;
   while(cin >> w >> h && (h || w)){
      int p = 0;
      for(int i=0;i<h;++i){
         for(int j=0;j<w;++j){
            cin >> data[i][j];
            if(data[i][j] == 'E' ||
               data[i][j] == 'N' ||
               data[i][j] == 'W' ||
               data[i][j] == 'S') ++p;
         }
      }
      for(int i=0;i<h;++i){
         for(int j=0;j<w;++j){
            next[i][j] = data[i][j];
         }
      }
      int t;
      for(t=1;t<=180;++t){
         for(int i=0;i<h;++i){
            for(int j=0;j<w;++j){
               if(data[i][j] == '#' ||
                  data[i][j] == '.' ||
                  data[i][j] == 'X') continue;
               for(int k=0;k<4;++k){
                  int d = (ctoi[data[i][j]] + 3 + k) % 4;
                  int ty = i + dy[d];
                  int tx = j + dx[d];
                  if(ty<0 || ty>=h) continue;
                  if(tx<0 || tx>=w) continue;
                  if(data[ty][tx] == '.' || data[ty][tx] == 'X'){
                     data[i][j] = itoc[d];
                     break;
                  }
               }
            }
         }
         for(int i=0;i<h;++i){
            for(int j=0;j<w;++j){
               if(data[i][j] == '.' || data[i][j] == 'X'){
                  for(int k=0;k<4;++k){
                     int ty = i + dy[k];
                     int tx = j + dx[k];
                     if(ty<0 || ty>=h) continue;
                     if(tx<0 || tx>=w) continue;
                     if(data[ty][tx] == '#' ||
                        data[ty][tx] == '.' ||
                        data[ty][tx] == 'X') continue;
                     if(abs(ctoi[data[ty][tx]] - k) == 2){
                        if(data[i][j] == 'X') --p;
                        else next[i][j] = data[ty][tx];
                        next[ty][tx] = '.';
                        break;
                     }
                  }
               }
            }
         }
         copy();
         if(p == 0) break;
      }
      if(t > 180) cout << "NA" << endl;
      else cout << t << endl;
   }
   return 0;
}

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()){
		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)
	cout<<cnt-1<<endl;
	else
	cout<<"NA"<<endl;
	}
	return 0;
}