#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define rep(i,n) for (int i=0;i<(int)(n);i++)
#define codefor int test;scanf("%d",&test);while(test--)
#define yn(ans) if(ans)printf("Yes\n");else printf("No\n")
#define YN(ans) if(ans)printf("YES\n");else printf("NO\n")
#define umap unordered_map
#define uset unordered_set
using namespace std;
using ll = long long;
const int MOD=1000000007;
//入力系
void scan(int& a){scanf("%d",&a);}
void scan(long long& a){scanf("%lld",&a);}
template<class T> void scan(T& a){cin>>a;}
template<class T> void scan(vector<T>& vec){for(auto&& it:vec)scan(it);}
void in(){}
template <class Head, class... Tail> void in(Head& head, Tail&... tail){scan(head);in(tail...);}
//出力系
void print(const int& a){printf("%d",a);}
void print(const long long& a){printf("%lld",a);}
void print(const double& a){printf("%.15lf",a);}
template<class T> void print(const T& a){cout<<a;}
template<class T> void print(const vector<T>& vec){if(vec.empty())return;print(vec[0]);for(auto it=vec.begin();++it!= vec.end();){putchar(' ');print(*it);}}
void out(){putchar('\n');}
template<class T> void out(const T& t){print(t);putchar('\n');}
template <class Head, class... Tail> void out(const Head& head,const Tail&... tail){print(head);putchar(' ');out(tail...);}
//デバッグ系
template<class T> void dprint(const T& a){cerr<<a;}
template<class T> void dprint(const vector<T>& vec){if(vec.empty())return;cerr<<vec[0];for(auto it=vec.begin();++it!= vec.end();){cerr<<" "<<*it;}}
void debug(){cerr<<endl;}
template<class T> void debug(const T& t){dprint(t);cerr<<endl;}
template <class Head, class... Tail> void debug(const Head& head, const Tail&... tail){dprint(head);cerr<<" ";debug(tail...);}

struct Node{
        int parent=-1,sibling=-1,left=-1,right=-1;
};

/*先行順巡回*/
void preParse(int n,vector<Node> &tree,vector<int> &order){
    if(n==-1){
        return;
    }
    order.push_back(n);
    preParse(tree[n].left,tree,order);
    preParse(tree[n].right,tree,order);
}

/*中間順巡回*/
void inParse(int n,vector<Node> &tree,vector<int> &order){
    if(n==-1){
        return;
    }
    inParse(tree[n].left,tree,order);
    order.push_back(n);
    inParse(tree[n].right,tree,order);
}

/*後行順巡回*/
void postParse(int n,vector<Node> &tree,vector<int> &order){
    if(n==-1){
        return;
    }
    postParse(tree[n].left,tree,order);
    postParse(tree[n].right,tree,order);
    order.push_back(n);
}

int main(){
    int n;
    in(n);
    vector<Node> Tree(n);
    int a,b,c;
    rep(i,n){
        in(a,b,c);
        Tree[a].left=b;
        Tree[a].right=c;
        if(b!=-1&&c!=-1){
            Tree[b].sibling=c;
            Tree[c].sibling=b;
        }
        if(b!=-1)Tree[b].parent=a;
        if(c!=-1)Tree[c].parent=a;
    }
    int root;
    rep(i,n){
        if(Tree[i].parent==-1){
            root=i;
            break;
        }
    }
    vector<int> preorder,inorder,postorder;
    preParse(root,Tree,preorder);
    inParse(root,Tree,inorder);
    postParse(root,Tree,postorder);
    printf("Preorder\n ");
    out(preorder);
    printf("Inorder\n ");
    out(inorder);
    printf("Postorder\n ");
    out(postorder);
}


Measured memory_bytes: 3264