/*调用算法中函数求写一个排序*/
#include <iostream>
#include<algorithm>
#include<queue>
#include<stack>
#include<cmath>
#include<string.h>
#include<stdio.h>
#include<stdlib.h>
using namespace std;
#define maxn 2600000
typedef int State[9];
State st[maxn],goal;
int dist[maxn];
const int dx[]= {-1,1,0,0};
const int dy[]= {0,0,-1,1};
int vis[36288],fact[9];
/*void init_lookup_table()
{
int i;
fact[0]=1;
for(i=0;i<9;i++)
fact[i]=fact[i-1]*i;
}
int try_to_insert(int s)
{
int code=0,i,j,cnt;//把st[s]映射到整数code
for(i=0;i<9;i++)
{
cnt=0;
for(j=i+1;j<9;j++)
if(st[s][j]<st[s][i])
cnt++;
code+=fact[8-i]*cnt;
}
if(vis[code])
return 0;
return vis[code]=1;
}*/
const int MAXHASHSIZE = 1000003;
int head[MAXHASHSIZE],next[maxn];
void init_lookup_table()
{
memset(head,0,sizeof(head));
}
int hash(State & s)
{
int v =0;
for(int i=0; i<9; i++)
v=v*10+s[i];
return v % MAXHASHSIZE;
}
int try_to_insert(int s)
{
int h=hash(st[s]);
int u=head[h];
while(u)
{
if(memcmp(st[u],st[s],sizeof(st[s]))==0)
return 0;
u=next[u];
}
next[s]=head[h];
head[h]=s;
return 1;
}
int bfs()
{
int y,d;
init_lookup_table();
int front =1,rear =2;
while(front<rear)
{
State & s =st[front];
if(memcmp(goal,s,sizeof(s))==0)
return front;
int z;
for(z=0; z<9; z++)
if(!s[z])
break;
int x =z/3;
y=z%3;
for(d = 0; d <4; d++)
{
int newx =x +dx[d];
int newy =y +dy[d];
int newz =newx*3+newy;
if(newx>=0&&newx<3&&newy>=0&&newy<3)
{
State &t =st[rear];
memcpy(&t,&s,sizeof(s));
t[newz]=s[z];
t[z]=s[newz];
dist[rear]=dist[front]+1;
if(try_to_insert(rear))
rear++;
}
}
front++;
}
return 0;
}
int main()
{
int i;
while(1)
{
for(i=0; i<9; i++)
scanf("%d",&st[1][i]);
for(i=0; i<9; i++)
scanf("%d",&goal[i]);
int ans=bfs();
if(ans>0)
printf("%d\n",dist[ans]);
else
printf("-1\n");
}
return 0;
}
/*
2 6 4 1 3 7 0 5 8
8 1 5 7 3 6 4 0 2
31
*/
