#include<iostream>
#include<cstdio>
#define N 100
#define M 10000
using namespace std;
int read()
{
	char c=0;
	int sum=0;
	while (c<'0'||c>'9') c=getchar();
	while ('0'<=c&&c<='9') sum=sum*10+c-'0',c=getchar();
	return sum;
}
int n,m,rt[N+1],depth[N+1],fa[N+1],X[M+1],Y[M+1],tong[N+1],length;
bool used[N+1],E[N+1][N+1];
void dfs(int x)
{
	used[x]=1;
	for (int i=1;i<=n;++i)
		if (E[x][i]&&!used[i])
			fa[i]=x,depth[i]=depth[x]^1,dfs(i);
	return;
}
int find(int x)
{
	if (rt[x]==x) return x;
	return rt[x]=find(rt[x]);
}
void unionn(int x,int y)
{
	if (find(x)!=find(y)) rt[find(x)]=find(y);
	return;
}
int main()
{
	int d;
	bool op;
	n=read(),m=read();
	for (int i=1;i<=m;++i) X[i]=read()+1,Y[i]=read()+1,E[X[i]][Y[i]]=E[Y[i]][X[i]]=1;
	if (m==((n*(n-1))>>1))
	{
		printf("%d\n",n);
		for (int i=1;i<=n;++i)
		{
			for (int j=1;j<=n;++j) rt[j]=j;
			for (int j=1;j<=n-1;++j)
				if ((j&1)==(i&1))
					unionn(j,j+1);
			for (int j=1;j<=n;++j) printf("%d ",find(j));
			puts("");
		}
		return 0;
	}
	for (int i=1;i<=m;++i)
	{
		for (int j=1;j<=n;++j) rt[j]=j,used[j]=fa[j]=0;
		for (int j=1;j<=m;++j)
			if (X[j]!=X[i]&&X[j]!=Y[i]&&Y[j]!=X[i]&&Y[j]!=Y[i])
				unionn(X[j],Y[j]);
		op=1,used[X[i]]=used[Y[i]]=1,depth[X[i]]=0,depth[Y[i]]=1;
		for (int j=1;j<=n;++j)
			if (j!=X[i]&&j!=Y[i]&&find(j)==j)
			{
				d=0;
				for (int k=1;k<=n;++k)
					if (find(k)==j&&E[k][X[i]]!=E[k][Y[i]])
						d=k;
				if (!d)
				{
					op=0;
					break;
				}
				if (E[d][X[i]]) fa[d]=X[i];
				else fa[d]=Y[i];
				depth[d]=depth[fa[d]]^1,dfs(d);
			}
		if (op)
		{
			printf("%d\n",n<<1);
			for (int j=1;j<=(n<<1);++j)
			{
				for (int k=1;k<=n;++k) rt[k]=k;
				unionn(X[i],Y[i]);
				for (int k=1;k<=n;++k)
					if (fa[k]&&depth[k]==(j&1))
						unionn(k,fa[k]);
				for (int k=1;k<=n;++k) printf("%d ",find(k));
				puts("");
			}
			return 0;
		}
	}
	return 0;
}