#include <bits/stdc++.h>
using namespace std;
map<string,int> m;
map<string,bool> m1;
queue<string> q;
signed main() {
	string s;
	cin>>s;
	q.push(s);
	m[s]=0;
	m1[s]=true;
	while(!q.empty()) {
		string p=q.front(),p1;
		q.pop();
		if(p=="123804765") {
			cout<<m[p];
			break;
		}
		for(int i=0;i<9;i++) {
			if(p[i]=='0') {
				p1=p;
				if(i-3>=0) swap(p1[i],p1[i-3]);
				if(!m1[p1]&&i-3>=0) {
					q.push(p1);
					m[p1]=m[p]+1;
					m1[p1]=true;
				}
				p1=p;
				if(i+3<=8) swap(p1[i],p1[i+3]);
				if(!m1[p1]&&i+3<=8) {
					q.push(p1);
					m[p1]=m[p]+1;
					m1[p1]=true;
				}
				p1=p;
				if(i-1>=0) swap(p1[i],p1[i-1]);
				if(!m1[p1]&&i-1>=0) {
					q.push(p1);
					m[p1]=m[p]+1;
					m1[p1]=true;
				}
				p1=p;
				if(i+1<=8) swap(p1[i],p1[i+1]);
				if(!m1[p1]&&i+1<=8) {
					q.push(p1);
					m[p1]=m[p]+1;
					m1[p1]=true;
				}
				break;
			}
		}
	}
}