#include<bits/stdc++.h>
using namespace std;
struct node{
	string s;
	int step, f;
	int id;
	bool operator<(const node& y)const{
		return f > y.f;
	}
};
int xd[4] = {0, 0, 1, -1};
int yd[4] = {1, -1, 0, 0};
string s;
string cmp = "123804765";
set<string> st;

int h(string a){
	int res = 0;
	for(int i = 0; i < 9; i++){
      if(a[i] == '0')continue; ///这里去点就卡样例12
    //201534786
    //19                       
		if(cmp[i] != a[i])res++;
	}
	return res;
}

int Astar(){
	if(!h(s))return 0;
	int id = 0;
	for(int i = 0; i < 9; i++){
		
		if(s[i] == '0'){
			id = i;
			break;
		}
	}
	priority_queue<node> q;
	int step = h(s);
	q.push(node{s, 0, step, id});
	st.insert(s);
	while(q.size()){
		node p = q.top();
		q.pop();
		int idx = p.id / 3;
		int idy = p.id % 3;
		for(int i = 0; i < 4; i++){
			int idxx = idx + xd[i];
			int idyy = idy + yd[i];
			if(idxx >= 0 && idxx < 3 && idyy >= 0 && idyy < 3){
				int idd = idxx * 3 + idyy;
				string ss = p.s;
				swap(ss[p.id], ss[idd]);
				if(st.find(ss) == st.end()){
					st.insert(ss);
					int hs = h(ss);
					if(!hs){
						return p.step  + 1;
					}
					q.push(node{ss, p.step + 1, p.step + 1 + hs, idd});
				}
			}
		}
	}
	return -1;
}


int main()
{
	cin >> s;
	cout << Astar();
	return 0;
 }