// compile: make data
// run: time ./data < data.in
#include <bits/stdc++.h>
using namespace std;
// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#ifdef LOCAL
#include <debug/codeforces.h>
#define debug(x...) _debug_print(#x, x);
#define Debug(x...) _debug_print_format(#x, x);
std::ifstream terminal("/dev/tty");
#define PP cerr<<"\033[1;30mpause...\e[0m",terminal.ignore();
#else
#define debug(x...)
#define Debug(x...)
#define PP
#endif
template<typename...Args> void print_(Args...args){((cout<<args<<" "),...)<<endl;}
#define rep(i,a,b) for(int i=(a);i<(int)(b);++i)
#define sz(v) ((int)(v).size())
#define print(...) print_(__VA_ARGS__);
#define FIND(a, x) ((find(a.begin(),a.end(),(x))!=a.end())?1:0)
#define cmin(x,...) x=min({(x),__VA_ARGS__})
#define cmax(x,...) x=max({(x),__VA_ARGS__})
#define INTMAX (int)(9223372036854775807)
#define INF (int)(1152921504606846976)
#define NaN (int)(0x8b88e1d0595d51d1)
#define double long double
#define int long long
#define uint unsigned long long
#define MAXN 200010

struct graph {
    struct node {
        int u, v, w;
        int idx;
        bool operator<(const node &other) const {return w < other.w; }
        bool operator==(const node &other) const {return v == other.v && w == other.w; }
    };
    vector<vector<node>> e;
    vector<vector<int>> invid;
    node &inv(node &edge) {return e[edge.v][invid[edge.u][edge.idx]]; }

    int n;
    bool directed;
    graph(int V, bool D = 0) {
        n = V;
        e.resize(n), invid.resize(n);
        directed = D;
    }
    void add_edge(int u, int v, int w = 1, int wb = 1) {
        e[u].push_back(node{u, v, w, sz(e[u])});
        if (!directed) {
            e[v].push_back(node{v, u, wb, sz(e[v])});
            invid[u].push_back(sz(e[v]) - 1);
            invid[v].push_back(sz(e[u]) - 1);
        }
    }
    void graphviz_dump(int plus = 0, string filename = "graph.dot") {
        ofstream gf; gf.open(filename);
        gf << (directed ? "digraph" : "graph") << " {\n";
        gf << "    "; rep(i, 0, n) gf << i+plus << " ;"[i==n-1]; gf << endl;
        string notation = directed ? " -> " : " -- ";
        bool weighted = 0;
        for (auto es: e) for (auto edge: es) if (edge.w != 1) weighted = 1;
        rep(u, 0, n) {
            for (auto edge: e[u]) {
                int v = edge.v, w = edge.w;
                if (!directed && u > v) continue;
                gf << "    " << u+plus << notation << v+plus << (weighted ? " ;\n" : ";\n");
            }
        }
        gf << "}\n";
    }
    int bfs(int s, int t) {
        if (s == t) return 0;
        queue<int> q; q.push(s);
        vector<int> dis(n, INF); dis[s] = 0;
        while (!q.empty()) {
            int u = q.front(); q.pop();
            for (auto &edge: e[u]) {
                int v = edge.v;
                if (dis[v] != INF) continue;
                dis[v] = dis[u] + 1;
                if (v == t) return dis[v];
                q.push(v);
            }
        }
        return -1;
    }
};

int p2i(vector<int> &a, int base = 0) {
    int n = a.size();
    vector<int> pos(n), f(n);
    rep(i, 0, n) pos[i] = f[i] = i;
    int res = 0;
    for (int i = 0, m = 1; i < n-1; ++i) {
        res += m * pos[a[i]-base];
        m *= n - i;
        pos[f[n-i-1]] = pos[a[i]-base];
        f[pos[a[i]-base]] = f[n-i-1];
    }
    return res;
}
vector<int> i2p(int n, int k, int base = 0) {
    vector<int> a(n), f(n);
    rep(i, 0, n) f[i] = i;
    for (int i = 0, m = k, ind; i < n; ++i) {
        ind = m % (n-i);
        m /= (n-i);
        a[i] = f[ind] + base;
        f[ind] = f[n-i-1];
    }
    return a;
}

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

    graph g(362880, 1);
    rep(mask, 0, 362880) {
        auto v = i2p(9, mask);
        rep(i, 0, 9) {
            if (i%3 < 2) {
                int j = i + 1;
                swap(v[i], v[j]);
                g.add_edge(mask, p2i(v));
                swap(v[i], v[j]);
            }
            if (i/3 < 2) {
                int j = i + 3;
                swap(v[i], v[j]);
                g.add_edge(mask, p2i(v));
                swap(v[i], v[j]);
            }
        }
    }
    vector<int> dest = {1, 2, 3, 4, 5, 6, 7, 8, 0};
    vector<int> src(9);
    rep(i, 0, 9) {
        cin >> src[i];
        if (src[i] == 9) src[i] = 0;
    }
    int res = g.bfs(p2i(src), p2i(dest));
    cout << res << endl;

    return 0;
}