Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	io := NewIo()
	defer io.Flush()
	N := io.NextInt()
	nodes := make([]Node, N*N+1)
	for i := 0; i < 2*N*N-2*N; i++ {
		a, b := io.NextInt(), io.NextInt()
		nodes[a].adj = append(nodes[a].adj, b)
		nodes[b].adj = append(nodes[b].adj, a)
	}
	ninja(nodes, N, io)
}

type Node struct {
	adj []int
}

func ninja(nodes []Node, N int, io *Io) {
	used := make([]bool, N*N+1)
	m := make([][]int, N)
	fst := 0
	for i := 0; i < N; i++ {
		m[i] = make([]int, N)
		for j := 0; j < N; j++ {
			if len(nodes[i*N+j].adj) == 2 {
				fst = i*N + j
			}
		}
	}
	m[0][0] = fst
	used[fst] = true
	for j := 1; j < N; j++ {
		u := 0
		deg := 3
		if j == N-1 {
			deg = 2
		}
		for _, v := range nodes[m[0][j-1]].adj {
			if !used[v] && len(nodes[v].adj) == deg {
				u = v
			}
		}
		m[0][j] = u
		used[u] = true
	}
	for i := 1; i < N; i++ {
		for j := 0; j < N; j++ {
			u := 0
			for _, v := range nodes[m[i-1][j]].adj {
				if !used[v] {
					u = v
				}
			}
			m[i][j] = u
			used[u] = true
		}
	}
	for _, a := range m {
		io.PrintIntSlice(a)
	}
}

// I/O template
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

func NewIo() *Io {
	return &Io{
		reader: bufio.NewReader(os.Stdin),
		writer: bufio.NewWriter(os.Stdout),
	}
}

func (io *Io) Flush() {
	err := io.writer.Flush()
	if err != nil {
		panic(err)
	}
}

func (io *Io) NextLine() string {
	var buff []byte
	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buff = append(buff, line...)
		if !isPrefix {
			break
		}
	}
	return string(buff)
}

func (io *Io) Next() string {
	for io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}
	s := io.tokens[io.nextToken]
	io.nextToken++
	return s
}

func (io *Io) NextInt() int {
	i, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) NextFloat() float64 {
	i, err := strconv.ParseFloat(io.Next(), 64)
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) Println(a ...interface{}) {
	fmt.Fprintln(io.writer, a...)
}

func (io *Io) Printf(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format, a...)
}

func (io *Io) PrintIntSlice(a []int) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func (io *Io) PrintStringSlice(a []string) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func Log(name string, value interface{}) {
	fmt.Fprintf(os.Stderr, "%s=%+v\n", name, value)
}

func ExampleIo() {
	io := NewIo()
	defer io.Flush()
	a := make([]int, 0, 3)
	a[0], a[1], a[2] = io.NextInt(), io.NextInt(), io.NextInt()
	io.Println(a)
	io.PrintIntSlice(a)
	Log("io", a)
}

C++: #include<bits/stdc++.h>
using namespace std;
using Int = long long;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}


template <typename T>
vector<T> dijkstra(int s,vector<vector<pair<int, T> > > & G){  
  const T INF = numeric_limits<T>::max();    
  using P = pair<T, int>;
  int n=G.size();
  vector<T> d(n,INF);
  vector<int> b(n,-1);
  priority_queue<P,vector<P>,greater<P> > q;
  d[s]=0;
  q.emplace(d[s],s);
  while(!q.empty()){
    P p=q.top();q.pop();
    int v=p.second;
    if(d[v]<p.first) continue;
    for(auto& e:G[v]){
      int u=e.first;
      T c=e.second;
      if(d[u]>d[v]+c){
        d[u]=d[v]+c;
        b[u]=v;
        q.emplace(d[u],u);
      }
    }
  }
  return d;
}

//INSERT ABOVE HERE
const int MAX = 101;
int ans[MAX][MAX];
signed main(){
  int n;
  cin>>n;
  using P = pair<int, int>;
  vector<vector<P> > G(n*n);
  for(int i=0;i<2*n*n-2*n;i++){
    int a,b;
    cin>>a>>b;
    a--;b--;
    G[a].emplace_back(b,1);
    G[b].emplace_back(a,1);
  }
  vector<int> cs;
  for(int i=0;i<n*n;i++)
    if(G[i].size()==2u) cs.emplace_back(i);

  vector<vector<int> > ds;
  for(int c:cs) ds.emplace_back(dijkstra(c,G));
  
  map<P, P> pos;
  for(int i=0;i<n;i++)
    for(int j=0;j<n;j++)
      pos[P(i+j,i+(n-1-j))]=P(i,j);

  int x=0;
  int y=ds[x][cs[1]]==n-1?1:2;
  for(int i=0;i<n*n;i++){
    int p,q;
    tie(p,q)=pos[P(ds[x][i],ds[y][i])];
    ans[p][q]=i;
  }
  
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
      if(j) cout<<" ";
      cout<<ans[i][j]+1;
    }
    cout<<endl;
  }
  return 0;
}