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>
#include <queue>
#include <deque>
#include <string>
#include <cmath>
#include <cstdio>
#define FOR(I,A,B) for(int I =(A);I<(B);++I)
#define FORE(I,B) for(int I =1;I<=(B);++I)
#define REP(I,A) FOR(I,0,A)
const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
const char dc[]={'E','N','W','S'};
const char dcc[]={'e','n','w','s'};
using namespace std;

int main() {
	// your code goes here
	int W,H;
	while (cin >> W >> H && W){
	char tmp;
	char maps[32][32]={};
	FORE(i,H)
		FORE(j,W)
			cin >> maps[i][j];
	bool ans;
	int next=0;
	while(true){
		ans=false;
		FORE(jj,W){
			int j=W-jj;
			FORE(i,H){
				REP(k,4)
					if(maps[i][j]==dc[k]){
						REP(l,4){
							int n=(k+l+3)%4;
							if(maps[i+dy[n]][j+dx[n]]=='.'){
								maps[i][j]='x';
								maps[i+dy[n]][j+dx[n]]=dcc[n];
							}
							else if(maps[i+dy[n]][j+dx[n]]=='n' && dc[n]=='E'){
								maps[i][j]='x';
								maps[i+dy[n]][j+dx[n]]=dcc[n];
								maps[i+1][j+1]='N';
							}
							else if(maps[i+dy[n]][j+dx[n]]=='X')
								maps[i][j]='x';
							else{
							REP(g,4)
								if(maps[i+dy[n]][j+dx[n]]==dcc[g]){
									maps[i][j]=dc[n];
									goto label;
								}
								continue;
							}
							label:
							break;
						}
					ans=true;
					break;
					}
			}
		}
		FORE(i,H){
			FORE(j,W){
				if(maps[i][j]=='x')
					maps[i][j]='.';
				REP(k,4)
					if(maps[i][j]==dcc[k])
						maps[i][j]=dc[k];
			//	cout << maps[i][j];
			}
	//	cout << endl;
		}
		if(!ans || next>180)
			break;
		next++;
	}
	if(next>180)
	cout << "NA" << endl;
	else 
	cout << next << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<string>

using namespace std;
#define rep(i,n) for ( int i = 0; i < n; i++ )
#define REP(i, b, e) for ( int i = b; i <= e; i++ )
#define MAX 100
#define LIMIT 180
#define BLOCK '#'
#define SPACE '.'
#define EXIT 'X'
static const string DIR = "ENWS";
static const int di[4] = {0, -1, 0, 1};
static const int dj[4] = {1, 0, -1, 0};
int H, W;
char G[MAX+2][MAX+2];

char oposite( int r ){
    return DIR[(r+2)%4];
}

bool isPerson(char ch){
    rep(d, 4) if ( ch == DIR[d] ) return true;
    return false;
}

int getDirection(char ch){
    rep(d, 4) if ( ch == DIR[d] ) return d;
}

int chengeDirection(){
    int nperson = 0;
    REP(i, 1, H) REP(j, 1, W){
	if ( !isPerson(G[i][j]) ) continue;
	nperson++;
	int curd = getDirection(G[i][j]);
	int v = curd;
	curd = ((curd == 0) ? 3 : curd-1);
	for ( int r = curd; r < curd + 4; r++ ){
	    char ch = G[i+di[r%4]][j+dj[r%4]];
	    if ( ch == SPACE || ch == EXIT ){
		v = r%4;
		break;
	    }
	}
	G[i][j] = DIR[v];
    }
    return nperson;
}

void move(){
    bool possible[MAX+2][MAX+2];
    rep(i, H+2) rep(j, W+2 ) possible[i][j] = false;

    REP(i, 1, H) REP(j, 1, W){
	if ( G[i][j] == SPACE || G[i][j] == EXIT){
	    for ( int r = 0; r < 4; r++ ){
		char target = G[i+di[r]][j+dj[r]];
		if ( isPerson(target) && target == oposite(r) ){
		    possible[i+di[r]][j+dj[r]] = true;
		    break;
		}
	    }
	}
    }

    REP(i, 1, H) REP(j, 1, W){
	if ( !isPerson(G[i][j]) || !possible[i][j] ) continue;

	int ni, nj;
	for ( int r = 0; r < 4; r++ ){
	    if ( DIR[r] == G[i][j] ) {
		ni = i + di[r];
		nj = j + dj[r];
		break;
	    }
	}

	if ( G[ni][nj] == EXIT ){
	    G[i][j] = SPACE;
	} else if ( G[ni][nj] == SPACE ){
	    G[ni][nj] = G[i][j];
	    G[i][j] = SPACE;
	}
    }
}

void trace(){
    REP(i, 1, H){
	REP(j, 1, W){
	    cout << G[i][j];
	}
	cout << endl;
    }
    cout << endl;
}

int main(){
    while(1){
	cin >> W >> H;
	if ( H == 0 && W == 0 ) break;
	rep(i,H+2) rep(j,W+2) G[i][j] = BLOCK;
	REP(i, 1, H) REP(j, 1, W) {
	    cin >> G[i][j];
	    char c = G[i][j];
	}
	
	int t = 0;
	while(1){
	    if ( t > LIMIT ) break;
	    if( !chengeDirection() ) break;
	    move();
	    t++;
	}
	if ( t > LIMIT ) cout << "NA" << endl;
	else cout << t <<  endl;
    }

    return 0;
}