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>
 
using namespace std;

int main() {
	int m[30][30],vx[4]={1,0,-1,0},vy[4]={0,-1,0,1};
    int i,j,k,w,h,t,cn,v,a,b;
    char c[30][30],g[4]={'E','N','W','S'};
    while(cin >> w >> h && w>0) {
		cn=0;
		for (i=0;i<h;i++) { 
			cin >> c[i];
			for (j=0;j<w;j++) {
				m[i][j]=-9;
				for (k=0;k<4;k++) if (g[k]==c[i][j]) { m[i][j]=k+1; cn++;}
			}
		} 
		
		for (t=1;t<181;t++) {
			for (i=0;i<h;i++) for (j=0;j<w;j++) {
				if (m[i][j]>0 && m[i][j]<5) {
					for (k=0;k<4;k++) {
						v=(m[i][j]+2+k) % 4; a=i+vy[v]; b=j+vx[v];
						if (a<0 || a>=h || b<0 || b>=w) continue; 
						if (c[a][b]!='#' && m[a][b]<1) {
							 m[i][j]=v+1;
							 if (m[a][b]<-((v+2) % 4)) m[a][b]=-((v+2) % 4);
							 break;
						 } 
					}
				}
			}
			
			for (i=0;i<h;i++) for (j=0;j<w;j++) {
				if (m[i][j]>-4 && m[i][j]<1) {
					v=-m[i][j];
					if (c[i][j]=='X')  {cn--; m[i][j]=-9;} else m[i][j]=((v+2) % 4)+1;
					m[i+vy[v]][j+vx[v]]=-9;
				}
			}
		if (cn==0) break;  
		}		
		if (t<181) cout << t << endl; else cout << "NA" << endl;
	}		   
	return 0;
}

C++: #include<iostream>
#include<vector>
#include<string>
#include<algorithm>
#include<map>
#include<set>
#include<utility>
#include<cmath>
#include<cstring>
#include<queue>
#include<cstdio>
#include<sstream>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define mp make_pair
#define all(in) in.begin(),in.end()
const double PI=acos(-1);
const double EPS=1e-8;
const int inf=1e9;
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
int main(){
	int dx[]={0,-1,0,1,0,-1,0,1};
	int dy[]={1,0,-1,0,1,0,-1,0};
	int n,m;
	while(cin>>m>>n,n+m){
		vector<string>in(n);
		rep(i,n)cin>>in[i];
		rep(i,n)rep(j,m)if(in[i][j]=='N')in[i][j]='0';
		else if(in[i][j]=='E')in[i][j]='3';
		else if(in[i][j]=='S')in[i][j]='2';
		else if(in[i][j]=='W')in[i][j]='1';
		int c=0;
		rep(i,n)rep(j,m)if(isdigit(in[i][j]))c++;
		rep(q,181){
			if(q==180){
				cout<<"NA"<<endl;
				break;
			}
			vector<string>tmp=in;
			rep(i,n)rep(j,m)if(isdigit(tmp[i][j]))tmp[i][j]='.';
			rep(i,n)for(int j=m-1;j>=0;j--)if(isdigit(in[i][j])){
				int t=in[i][j]-'0';
				rep(k,4)if(in[i+dx[t+k]][j+dy[t+k]]!='#'&&
					!isdigit(in[i+dx[t+k]][j+dy[t+k]])){
					//if(!isdigit(tmp[i+dx[t+k]][j+dy[t+k]]))
					if(in[i+dx[t+k]][j+dy[t+k]]=='X'){
						c--;
						if(c==0){
							cout<<q+1<<endl;
							goto end;
						}
					}else if(!isdigit(tmp[i+dx[t+k]][j+dy[t+k]]))
						tmp[i+dx[t+k]][j+dy[t+k]]=(in[i][j]-'0'+k+3)%4+'0';
					else tmp[i][j]=in[i][j];
					goto eend;
				}
				tmp[i][j]=in[i][j];
				eend:;
			}
			in=tmp;
//			rep(i,n)cout<<in[i]<<endl;cout<<endl;
		}
		end:;
	}
}