#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <set>
#include <cstring>
#include <cstdlib>
using namespace std;


const int INF=100000000;
// ®©¹éêði[·éXg
vector<int> d[13];

// »ê¼êÌê©çá¤êÖÚ®·éÌÉKvÈ}nb^£
int mhd[13][13];
const int V=13;

void warshall_floyd(){
    for(int k = 0; k < V; k++)
        for(int i = 0; i < V; i++)
            for(int j = 0; j < V; j++)
                mhd[i][j]=min(mhd[i][j],mhd[i][k]+mhd[k][j]);
}

int main(){

    d[0].push_back(2);

    d[1].push_back(2);
    d[1].push_back(5);

    d[2].push_back(0);
    d[2].push_back(1);
    d[2].push_back(3);
    d[2].push_back(6);

    d[3].push_back(2);
    d[3].push_back(7);

    d[4].push_back(5);

    d[5].push_back(1);
    d[5].push_back(4);
    d[5].push_back(6);
    d[5].push_back(9);

    d[6].push_back(2);
    d[6].push_back(5);
    d[6].push_back(7);
    d[6].push_back(10);

    d[7].push_back(3);
    d[7].push_back(6);
    d[7].push_back(8);
    d[7].push_back(11);

    d[8].push_back(7);

    d[9].push_back(5);
    d[9].push_back(10);

    d[10].push_back(6);
    d[10].push_back(9);
    d[10].push_back(11);
    d[10].push_back(12);

    d[11].push_back(10);
    d[11].push_back(7);

    d[12].push_back(10);

    for(int i = 0; i < 13; i++)
        for(int j = 0; j < 13; j++)
            mhd[i][j]=INF;
    
    for(int i = 0; i < 13; i++){
        mhd[i][i]=0;
        // ¼Ú¹ª éÆ±ëÉRXg1ðãü
        for(int j = 0; j < d[i].size(); j++){
            int to=d[i][j];
            mhd[i][to]=1;
        }
    }

    warshall_floyd();

    while(1){
        set<vector<int> > no;
        vector<int> v;
        int cost=0;
        for(int j = 0; j < 13; j++){
            int t;
            cin>>t;
            if(t==-1)
                return 0;
            v.push_back(t);
            if(t!=0)
                cost+=mhd[t][j];
        }
        // Å©ç»ëÁÄ¢éê
        if(cost==0){
            cout<<0<<endl;
            continue;
        }
        queue<pair<int,vector<int> > > *prv=new queue<pair<int,vector<int> > >();
        queue<pair<int,vector<int> > > *nxt=new queue<pair<int,vector<int> > >();
        prv->push(make_pair(cost,v));
        int cnt=0;
        bool isGoal=false;
        // 20èÜÅTõð©¯é
        while(prv->size()){
            while(prv->size()){
                vector<int> b=prv->front().second;
                int cos=prv->front().first;    
                prv->pop();
                vector<int> emp;
                for(int i = 0; i < b.size(); i++)
                    if(b[i]==0)
                        emp.push_back(i);
                // óÌêðêÂIÑAJÚ·é
                for(int i = 0; i < emp.size(); i++){
                    int num=emp[i];
                    for(int j = 0; j < d[num].size(); j++){
                        // ¡ñg¤board
                        vector<int> bt=b;
                        // Ú®æ
                        int to=d[num][j];
                        if(bt[to]==0)
                            continue;
                        swap(bt[to],bt[num]);
                        if(no.find(bt)!=no.end())
                            continue;
                        no.insert(bt);
                        // Ú®æÌ]¿l(0ÉÈÁ½çI¹)
                        int toCost=cos-mhd[to][b[to]]+mhd[b[to]][num];
                        // goal
                        if(toCost==0){
                            isGoal=true;
                            break;
                        }
                        // »Ýn_©çS[É½Çè¯é©Ç¤©
                        // ³Èç}ëè
                        if(!(toCost>(19-cnt)))
                            nxt->push(make_pair(toCost,bt));
                    }
                    if(isGoal)
                        break;
                }
                if(isGoal)
                    break;
            }
            if(isGoal)
                break;
            swap(prv,nxt);
            cnt++;
            // 20èðz¦Ä¢é
            if(cnt>=20){
                break;
            }
        }
        if(isGoal){
            cout<<cnt+1<<endl;
        }
        else{
            cout<<"NA"<<endl;
        }
        delete prv,nxt;
    }

    return 0;
}

Measured memory_bytes: 0