#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;
typedef long long ll;
int ans = 123456780;
const int P = 1e6 + 7;
vector<int>v[P + 5];
int n;
int fx[] = { 1,-1,0,0 };
int fy[] = { 0,0,1,-1 };
bool find(int x)
{
    int y = x % P;
    for (int i = 0; i < v[y].size(); i++)
    {
        if (v[y][i] == x)
            return true;
    }
    return false;
}
struct node
{
    int val;
    int step;
};
void bfs()
{
    queue<node>q;
    q.push({ n,0 });
    while (!q.empty())
    {
        node u = q.front();
        q.pop();
        if (u.val == ans)
        {
            cout << u.step;
            return;
        }
        //状态转移
        int a[5][5];
        int x = u.val;
        int kx, ky;
        for (int i = 3; i >= 1; i--)
        {
            for (int j = 3; j >= 1; j--)
            {
                a[i][j] = x % 10;
                x /= 10;
                if (a[i][j] == 0)kx = i, ky = j;
            }
        }
        int b[5][5];
        for (int i = 0; i < 4; i++)
        {
            memcpy(b, a, sizeof(a));
            int nx = kx + fx[i];
            int ny = ky + fy[i];
            if (nx > 3 || ny > 3 || nx < 1 || ny < 1)
                continue;
            swap(b[nx][ny], b[kx][ky]);
            int nownum=0;
            for (int i = 1; i <= 3; i++)
            {
                for (int j = 1; j <= 3; j++)
                {
                    nownum *= 10;
                    nownum += b[i][j];
                }
            }
            if (find(nownum))
                continue;
            v[nownum % P].push_back(nownum);
            q.push({ nownum,u.step + 1 });
        }
    }
    cout << -1;
    return;
}
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    for (int i = 1; i <= 9; i++)
    {
        char x;
        cin >> x;
        n *= 10;
        if (x == 'x')
        {
            n += 0;
        }
        else
        {
            n += x - '0';
        }
    }
    v[n % P].push_back(n);
    bfs();
    return 0;
}