#include <cstdio>
#include <cstring>
#include <set>
using namespace std;
typedef int State[9];
const int maxState = 1000000;
State st[maxState], goal;
int dist[maxState];
const int dx[] = {-1, 1, 0, 0};
const int dy[] = { 0, 0, -1, 1};
int vis[362880], fact[9];
void init_lookup_table() {
fact[0] = 1;
for(int i = 1; i < 9; i++) {
fact[i] = fact[i - 1] * i;
}
}
int try_to_insert(int s) {
int code = 0;
for(int i = 0; i < 9; i++) {
int cnt = 0;
for(int 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 hashSize = 1000003;
int head[hashSize], next[maxState];
void init_lookup_table2() {
memset(head, 0, sizeof(head));
}
int hash(const State &s) {
int v = 0;
for(int i = 0; i < 9; i++) {
v = v * 10 + s[i];
}
return v % hashSize;
}
int try_to_insert2(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;
}
set<int> visited;
void init_lookup_table3() {
visited.clear();
}
int try_to_insert3(int s) {
int v = 0;
for(int i = 0; i < 9; i++) {
v = v * 10 + st[s][i];
}
if(visited.count(v)) {
return 0;
}
visited.insert(v);
return 1;
}
int bfs() {
init_lookup_table3();
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;
int y = z % 3;
for(int 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_insert3(rear)) {
rear++;
}
}
}
front++;
}
return 0;
}
int main() {
for(int i = 0; i < 9; i++) {
scanf("%d", &st[1][i]);
}
for(int 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;
}