#include <bits/stdc++.h>
using namespace std;
int n;
int ten[10];
map<int, int> dis;
queue<int> q;
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    ten[0] = 1;
    for (int i = 1; i <= 8; i++)
        ten[i] = ten[i - 1] * 10;
    q.push(n);
    dis[n] = 0;
    while (!q.empty() &&
           dis.find(123804765) == dis.end())
    {
        int now = q.front();
        q.pop();
        // 0 的位置、目标的位置
        int pos = -1, t;
        for (int i = 0; i <= 8; i++)
            if (now / ten[i] % 10 == 0)
            {
                pos = i;
                break;
            }
        // 上下左右
        for (int i = 1; i <= 4; i++)
        {
            if (i == 1)
                t = pos - 3;
            if (i == 2)
                t = pos + 3;
            if (i == 3)
            {
                if (pos % 3 == 0)
                    t = -1;
                else
                    t = pos - 1;
            }
            if (i == 4)
            {
                if (pos % 3 == 2)
                    t = -1;
                else
                    t = pos + 1;
            }
            if (0 <= t && t <= 8)
            {
                // pos 上是 0，t 上是 x
                int x = now / ten[t] % 10;
                int nxt = now - x * ten[t] + x * ten[pos];
                if (dis.find(nxt) == dis.end())
                {
                    dis[nxt] = dis[now] + 1;
                    q.push(nxt);
                }
            }
        }
    }
    cout << dis[123804765];
    return 0;
}