#include <bits/stdc++.h>
 
//    #include <boost/multiprecision/cpp_int.hpp>
// #define int long long
 #define inf  1000000007
// #define inf  998244353

 #define pa pair<int,int>
 #define ll long long
 #define pal pair<double,double>
 #define ppap pair<pa,int>
  #define PI 3.14159265358979323846
  #define paa pair<int,char>
  #define  mp make_pair
  #define  pb push_back
  #define EPS (1e-8)
                                          
    int dx[8]={0,1,0,-1,1,1,-1,-1};
    int dy[8]={1,0,-1,0,-1,1,1,-1};
                                            using namespace std;
                                   			class pa3{
                                            	public:
                                            	int x;
                                   				int y,z;
                                            	pa3(int x=0,int y=0,int z=0):x(x),y(y),z(z) {}
                                            	bool operator < (const pa3 &p) const{
                                            		if(x!=p.x) return x<p.x;
                                            		if(y!=p.y) return y<p.y;
                                            		 return z<p.z;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                   				bool operator > (const pa3 &p) const{
                                            		if(x!=p.x) return x>p.x;
                                            		if(y!=p.y) return y>p.y;
                                            		 return z>p.z;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa3 &p) const{
                                            		return x==p.x && y==p.y && z==p.z;
                                            	}
                                            		bool operator != (const pa3 &p) const{
                                            			return !( x==p.x && y==p.y && z==p.z);
                                            	}
                                            
                                            };
                                            
                                            class pa4{
                                            	public:
                                            	int x;
                                            	int y,z,w;
                                            	pa4(int x=0,int y=0,int z=0,int w=0):x(x),y(y),z(z),w(w) {}
                                            	bool operator < (const pa4 &p) const{
                                            		if(x!=p.x) return x<p.x;
                                            		if(y!=p.y) return y<p.y;
                                            		if(z!=p.z)return z<p.z;
                                            		return w<p.w;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator > (const pa4 &p) const{
                                            		if(x!=p.x) return x>p.x;
                                            		if(y!=p.y) return y>p.y;
                                            		if(z!=p.z)return z>p.z;
                                            		return w>p.w;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa4 &p) const{
                                            		return x==p.x && y==p.y && z==p.z &&w==p.w;
                                            	}
                                            		
                                            
                                            };
                                            class pa2{
                                            	public:
                                            	int x,y;
                                            	pa2(int x=0,int y=0):x(x),y(y) {}
                                            	pa2 operator + (pa2 p) {return pa2(x+p.x,y+p.y);}
                                            	pa2 operator - (pa2 p) {return pa2(x-p.x,y-p.y);}
                                            	bool operator < (const pa2 &p) const{
                                            		return y != p.y ? y<p.y: x<p.x;
                                            	}
                                            	bool operator > (const pa2 &p) const{
                                            		return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa2 &p) const{
                                            		return abs(x-p.x)==0 && abs(y-p.y)==0;
                                            	}
                                            	bool operator != (const pa2 &p) const{
                                            		return !(abs(x-p.x)==0 && abs(y-p.y)==0);
                                            	}
                                            		
                                            
                                            };
                                            
 
                      
                                string itos( int i ) {
                                ostringstream s ;
                                s << i ;
                                return s.str() ;
                                }
                                 
                                int Gcd(int v,int b){
                                	if(v==0) return b;
                                	if(b==0) return v;
                                	if(v>b) return Gcd(b,v);
                                	if(v==b) return b;
                                	if(b%v==0) return v;
                                	return Gcd(v,b%v);
                                }
                 
                            
                                int mod;
int extgcd(int a, int b, int &x, int &y) {
    if (b == 0) {
        x = 1;
        y = 0;
        return a;
    }
    int d = extgcd(b, a%b, y, x);
    y -= a/b * x;
    return d;
}
pa operator+(const pa & l,const pa & r) {   
    return {l.first+r.first,l.second+r.second};                                    
}    
pa operator-(const pa & l,const pa & r) {   
    return {l.first-r.first,l.second-r.second};                                    
}  
                int beki(int wa,int rr,int warukazu){
                	if(rr==0) return 1%warukazu;
                	if(rr==1) return wa%warukazu;
                	wa%=warukazu;
                	if(rr%2==1) return ((ll)beki(wa,rr-1,warukazu)*(ll)wa)%warukazu;
                	ll zx=beki(wa,rr/2,warukazu);
                	return (zx*zx)%warukazu;
                }
 
                              
                int pr[100000];
                int inv[100000];
                

                
    			int comb(int nn,int rr){
    				if(rr<0 || rr>nn || nn<0) return 0;
    				int r=pr[nn]*inv[rr];
    				r%=mod;
    				r*=inv[nn-rr];
    				r%=mod;
    				return r;
    			}
               
                void gya(int ert){
                	pr[0]=1;
                	for(int i=1;i<=ert;i++){
                		pr[i]=((ll)pr[i-1]*i)%mod;
                	}
                		inv[ert]=beki(pr[ert],mod-2,mod);
                	for(int i=ert-1;i>=0;i--){
                		inv[i]=(ll)inv[i+1]*(i+1)%mod;
                	}
                }
                
              //   cin.tie(0);
    		//	ios::sync_with_stdio(false);
    			//priority_queue<pa3,vector<pa3>,greater<pa3>> pq;            
                 //sort(ve.begin(),ve.end(),greater<int>());
 //   mt19937(clock_per_sec);
  //  mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count()) ;

using T=array<array<int,4>,4>;

using ul=unsigned long long;
struct hoge{
	ul ban;
	int x;
	int y;
	int ato;
	int ima;
	bool operator<(const hoge& p) const{
		return ato+ima>p.ato+p.ima;
	}
};

queue<hoge> qu[10000];


signed main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
int h=3,w=3;
	
	//cin>>h>>w;
	T a;
	int sx,sy;
	
	int dis=0;
	ul state=0ull;
	
	for(int i=0;i<h;i++)for(int j=0;j<w;j++){
		cin>>a[i][j];
		a[i][j]--;
		if(a[i][j]>=0){
		dis+=abs(j-a[i][j]%w);
		dis+=abs(i-a[i][j]/w);
		}
		if(a[i][j]==-1)sx=i,sy=j,a[i][j]=8;
	}
	for(int i=2;i>=0;i--)for(int j=2;j>=0;j--){
		state<<=4;
		state|=a[i][j];
	}
	if(dis==0){
		cout<<0<<endl;
		return 0;
	}
	
	qu[dis].push({state,sx,sy,dis,0});
	//set<T> se;
	//se.insert(a);
	map<ul,int> ma;
	ma[state]=0;
	int it=0;
	int cnt=0;
	ul zen=0;
	for(int i=0;i<9;i++){
		zen*=16ull;
		zen+=15ull;
	}
	
	while(1){
		while(qu[it].size()==0){
			it++;
	//		cout<<it<<" "<<cnt<<endl;
		}

		hoge Z=qu[it].front();
		qu[it].pop();
		if(ma[Z.ban]<Z.ima)continue;
		cnt++;
		
		for(int r=0;r<4;r++){
			int x=Z.x+dx[r];
			int y=Z.y+dy[r];
			if(x<0 ||x>=h ||y<0 ||y>=w)continue;
			
			int t0=Z.x*3+Z.y;
			int t1=x*3+y;
			ul g0=(Z.ban>>(4*t0))&15ull;
			ul g1=(Z.ban>>(4*t1))&15ull;
			state=Z.ban;
			state&=(zen^(15ull<<(4*t0)));
			state&=(zen^(15ull<<(4*t1)));

			state|=g1<<(4*t0);
			state|=g0<<(4*t1);
			
			int zou=abs(Z.y-(int)(g1%3))+abs(Z.x-(int)(g1/3))-abs(y-(int)(g1%3))-abs(x-(int)(g1/3));
			
			
			//if(Z.ima+1+Z.ato+zou>45)continue;
		
			if(Z.ato+zou==0){
				cout<<Z.ima+1<<endl;
				return 0;
			}
			
			if(!ma.count(state) || ma[state]>Z.ima+1){
				ma[state]=Z.ima+1;
				qu[Z.ato+zou+Z.ima+1].push({state,x,y,Z.ato+zou,Z.ima+1});
			
			}
		}
	}
	
	return 0;
 }




Measured memory_bytes: 11668