Go: // BFS

package main

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

var scanner = bufio.NewScanner(os.Stdin)

var p = [15]int{}
var g = [13][4]int {
	// -1は存在しないマス目
	{2,-1,-1,-1},
	{2,5,-1,-1},{0,1,3,6},{2,7,-1,-1},
	{5,-1,-1,-1},{1,4,6,9},{2,5,7,10},{3,6,8,11},{7,-1,-1,-1},
	{5,10,-1,-1},{6,9,11,12},{7,10,-1,-1},
	{10,-1,-1,-1},
}

/*
　  ０ １ ２ ３ ４
 0 |／|／|  |／|／|
 1 |／|　|  |　|／|
 2 |　|　|  |　|　|
 3 |／|　|  |　|／|
 4 |／|／|  |／|／|
*/

var row = [13]int{0,1,1,1,2,2,2,2,2,3,3,3,4}
var col = [13]int{2,1,2,3,0,1,2,3,4,1,2,3,2}

type wolf struct {
	m [13]int
}

type pair struct {
	first wolf
	second int
}

func abs(a int) int {
	if a < 0 {
		return -a
	}
	return a
}

func print_board(board [13]int) {
	fmt.Println("--------------------------")
	fmt.Printf("        [%2d]\n", board[0])
	fmt.Printf("    [%2d][%2d][%2d]\n", board[1], board[2], board[3])
	fmt.Printf("[%2d][%2d][%2d][%2d][%2d]\n", board[4], board[5], board[6], board[7], board[8])
	fmt.Printf("    [%2d][%2d][%2d]\n", board[9], board[10], board[11])
	fmt.Printf("        [%2d]\n", board[12])
	fmt.Println("--------------------------")
}

func main() {
	for scanner.Scan() {
		p1, _ := strconv.Atoi(scanner.Text())
		if p1 == -1 {
			break
		}
		p[0]= p1
		scanner.Scan()
		buf1 := strings.Split(scanner.Text(), " ")
		p2, _ := strconv.Atoi(buf1[0])
		p3, _ := strconv.Atoi(buf1[1])
		p4, _ := strconv.Atoi(buf1[2])
		p[1], p[2], p[3] = p2, p3, p4
		scanner.Scan()
		buf2 := strings.Split(scanner.Text(), " ")
		p5, _ := strconv.Atoi(buf2[0])
		p6, _ := strconv.Atoi(buf2[1])
		p7, _ := strconv.Atoi(buf2[2])
		p8, _ := strconv.Atoi(buf2[3])
		p9, _ := strconv.Atoi(buf2[4])
		p[4], p[5], p[6], p[7], p[8] = p5, p6, p7, p8, p9
		scanner.Scan()
		buf3 := strings.Split(scanner.Text(), " ")
		p10, _ := strconv.Atoi(buf3[0])
		p11, _ := strconv.Atoi(buf3[1])
		p12, _ := strconv.Atoi(buf3[2])
		p[9], p[10], p[11] = p10, p11, p12
		scanner.Scan()
		p13, _ := strconv.Atoi(scanner.Text())
		p[12] = p13
		S := make(map[wolf]struct{})
		st := wolf{}
		for i := 0; i < 13; i++ {
			st.m[i] = p[i]
		}
		Q := make([]pair, 0)
		S[st] = struct{}{}
		Q = append(Q, pair{st, 0})
		yet := true
		for len(Q) > 0 {
			at := Q[0].first
			// print_board(at.m)
			cost := Q[0].second
			Q = Q[1:]
			ok := true
			for i :=1; i < 12; i++ {
				if at.m[i] != i {
					ok = false
				}
			}
			if ok {
				// print_board(at.m)
				yet = false
				fmt.Println(cost)
				break
			}
			now := cost
			for i := 0; i < 13; i++ {
				if at.m[i] != 0 {
					now += abs(row[i]-row[at.m[i]]) + abs(col[i]-col[at.m[i]])
				}
			}
			if now > 20 {
				continue
			}
			for i := 0; i < 13; i++ {
				if at.m[i] == 0 {
					for j := 0; j < 4; j++ {
						if ^g[i][j] != 0 {
							at.m[i], at.m[g[i][j]] = at.m[g[i][j]], at.m[i]
							if _, ok := S[at]; !ok {
								S[at] = struct{}{}
								Q = append(Q, pair{at, cost+1})
							}
							at.m[i], at.m[g[i][j]] = at.m[g[i][j]], at.m[i]
						}
					}
				}
			}
		}
		if yet {
			fmt.Println("NA")
		}
	}
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <cstring>
#include <cstdio>
#include <climits>

using namespace std;


#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define DEB 0

int board[7][7]; //1base
int sx[2], sy[2];
static const int dx[] = {0,0,1,-1};
static const int dy[] = {1,-1,0,0};

int calc(int y, int x){
    switch(board[y][x]){
    case 1: return abs(2-y)+abs(2-x);
    case 2: return abs(2-y)+abs(3-x);
    case 3: return abs(2-y)+abs(4-x);
    case 4: return abs(3-y)+abs(1-x);
    case 5: return abs(3-y)+abs(2-x);
    case 6: return abs(3-y)+abs(3-x);
    case 7: return abs(3-y)+abs(4-x);
    case 8: return abs(3-y)+abs(5-x);
    case 9: return abs(4-y)+abs(2-x);
    case 10: return abs(4-y)+abs(3-x);
    case 11: return abs(4-y)+abs(4-x);
    }
    return -1;
}
int dist(void){
    int ret = 0;
    if( board[1][3] ) ret += calc(1,3);
    rep(i,3) if( board[2][2+i] ) ret += calc(2,2+i);
    rep(i,5) if( board[3][1+i] ) ret += calc(3,1+i);
    rep(i,3) if( board[4][2+i] ) ret += calc(4,2+i);
    if( board[5][3] ) ret += calc(5,3);
    return ret;
}
bool isgoal(void){
    if( board[1][3]!=0 ) return false;
    rep(i,3) if( board[2][2+i]!=i+1 ) return false;
    rep(i,5) if( board[3][1+i]!=i+4 ) return false;
    rep(i,3) if( board[4][2+i]!=i+9 ) return false;
    if( board[5][3]!=0 ) return false;
    return true;
}

bool dfs(int cnt, int LIM, int py, int px){
    if( isgoal() ) return true;
    if( cnt+dist()>LIM ) return false;

    rep(i,2){
        if( board[sy[i]][sx[i]]!=0 ) exit(-1);
        rep(k,4){
            int tx = sx[i] + dx[k];
            int ty = sy[i] + dy[k];
            if( board[ty][tx]==-1 ) continue;
            swap(board[sy[i]][sx[i]], board[ty][tx]);
            swap(sx[i], tx); swap(sy[i],ty);
            if( dfs(cnt+1, LIM, ty, tx) ) return true;
            swap(sx[i], tx); swap(sy[i],ty);
            swap(board[sy[i]][sx[i]] ,board[ty][tx]);
        }
    }
    return false;
}
int solve(void){
    int ttx[2], tty[2];
    int tb[7][7];
    rep(i,2) ttx[i]=sx[i], tty[i]=sy[i];
    rep(i,7)rep(j,7) tb[i][j] = board[i][j];

    for(int lim = 0; lim < 21; lim++){
        rep(i,2) sx[i]=ttx[i], sy[i]=tty[i];
        rep(i,7) rep(j,7) board[i][j] = tb[i][j];
        if( dfs(0,lim,-1,-1) ) return lim;
    }
    return -1;
}
int main(){
    for(;;){
        memset(board, -1, sizeof(board));
        int sz = 0;

        scanf("%d",&board[1][3]); if( board[1][3]==-1 ) break;
        rep(i,3) scanf("%d",&board[2][2+i]);
        rep(i,5) scanf("%d",&board[3][1+i]);
        rep(i,3) scanf("%d",&board[4][2+i]);
        scanf("%d",&board[5][3]);

        // find space
        if( board[1][3]==0 ){ sx[sz]=3; sy[sz]=1; sz++; }
        rep(i,3) if( board[2][2+i]==0 ) { sx[sz]=2+i; sy[sz]=2; sz++; }
        rep(i,5) if( board[3][1+i]==0 ) { sx[sz]=1+i; sy[sz]=3; sz++; }
        rep(i,3) if( board[4][2+i]==0 ) { sx[sz]=2+i; sy[sz]=4; sz++; }
        if( board[5][3]==0 ){ sx[sz]=3; sy[sz]=5; sz++; }

        //printf("hoge:%d\n",dist());
        int ans = solve();
        if( ans!=-1 ) printf("%d\n",ans); else puts("NA");
    }
    return 0;
}

/*

//-------------------------------------------------------

#define N 5
#define REP(i, n) for ( int i = 0; i < (int)n; i++ )
#define LIMIT 20

static const int T[12][2] = {
    {-1, -1},
    {1, 1}, 
    {1, 2}, 
    {1, 3},
    {2, 0},
    {2, 1},
    {2, 2},
    {2, 3},
    {2, 4},
    {3, 1}, 
    {3, 2},
    {3, 3}
};
static const int g[N][N] = {
    {-1,-1, 0,-1,-1},
    {-1, 1, 2, 3,-1},
    { 4, 5, 6, 7, 8},
    {-1, 9,10,11,-1}, 
    {-1,-1, 0,-1,-1}
};

class Puzzle{
public:
    int C[N][N], mdist; //manhatta distance
    Puzzle(){}

    bool swapAdj( int si, int sj, int ti, int tj ){
        if ( ti < 0 || tj < 0 || ti >= N || tj >= N ) return false;
        if ( C[ti][tj] <= 0 ) return false;
        swap(C[ti][tj], C[si][sj]);
        int tti = T[C[si][sj]][0];
        int ttj = T[C[si][sj]][1];
        //mdist -= max(tti, ti)-min(tti, ti) + max(ttj, tj)-min(ttj, tj);
        //mdist += max(tti, si)-min(tti, si) + max(ttj, sj)-min(ttj, sj);
        //mdist -= abs(tti-ti)+abs(ttj-tj);
        //mdist += abs(tti-si)+abs(ttj-sj);
        return true;
    }

    bool isGoal(){
        REP(i, N) REP(j, N) if ( g[i][j] != C[i][j] ) return false;
        return true;
    }

    int getMD(){ // get initial manhattan distance
        int sum = 0;
        int ti, tj;
        REP(i, 5) REP(j, 5){
            if ( C[i][j] <= 0 ) continue;
            ti = T[C[i][j]][0];
            tj = T[C[i][j]][1];
            //sum += (max(ti, i)-min(ti, i) + max(tj, j) - min(tj, j));
            sum += abs(ti-i) + abs(tj-j);
        }
        return sum;
    }
};

int limit;

bool dfs( int depth, Puzzle P ){
    if ( P.isGoal() ) return true;
    if ( depth + P.getMD() > limit ) return false;

    static const int di[4] = {0, -1, 0, 1};
    static const int dj[4] = {1, 0, -1, 0};

    REP(i, N) REP(j, N){
        if ( P.C[i][j] != 0 ) continue;
        REP(r, 4){
            Puzzle v = P;
            if ( !v.swapAdj(i, j, i+di[r], j+dj[r]) ) continue;
            if ( dfs( depth + 1, v ) ) return true;
        }
    }

    return false;
}

int idp(Puzzle source){
    for ( limit = 0; limit <= LIMIT; limit++ ){
        //source.mdist = source.getMD();
        if ( dfs(0, source) ) return limit;
    }
    return INT_MAX;
}

int main(){
    Puzzle P;
    int top;

    while(1){
        cin >> top;
        if ( top == -1 ) break;
        REP(j, N) P.C[0][j] = -1;
        P.C[0][2] = top;
        for(int i = 1; i < N; i++) REP(j, N){
                if ( (i == 1 || i == 3) && (j == 0 || j == 4 ) ) P.C[i][j] = -1;
                else if ( i == 4 && j != 2 ) P.C[i][j] = -1;
                else cin >> P.C[i][j];
            }

        int cost = idp(P);
        if ( cost == INT_MAX ) cout << "NA" << endl;
        else cout << cost << endl;	
    }

    return 0;
}

*/