#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef basic_string<int> BI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
mt19937 mrand(random_device{}()); 
const ll mod=1000000007;
int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

const int N=201000;
namespace euler {
	const int V=301000,E=1010000;
	int edgenum,top,n;
	int vet[E],nxt[E],head[V],s[E],ru[V],cu[V],q[E],flag[E],d[V];
	void init(int nn) {
		edgenum=0; top=0; n=nn;
		rep(i,0,n) head[i]=d[i]=ru[i]=cu[i]=d[i]=0;
	}
	void add(int u,int v,int id)
	{
		//printf("? %d %d %d\n",u,v,id);
		d[u]++;
		vet[++edgenum]=v;
		flag[abs(id)]=0;
		nxt[edgenum]=head[u];
		head[u]=edgenum;
		s[edgenum]=id;
		ru[v]++;cu[u]++;
	}
	void dfs(int u)
	{
		for (int e=head[u];e;e=head[u])
		{
			while (e&&flag[abs(s[e])]) e=nxt[e];
			head[u]=e;
			if (e)
			{
				flag[abs(s[e])]=1;
				dfs(vet[e]);
				q[++top]=s[e];
			}
		}
	}
	VI solve() {
		rep(i,0,n) if (cu[i]!=ru[i]) return VI{0};
		rep(i,1,edgenum+1) {
			if (!flag[abs(s[i])]) dfs(vet[i]);
		}
		reverse(q+1,q+top+1);
		return VI(q+1,q+top+1);
	}
}

int n,m,k,deg[N];
vector<PII> e[N];
PII E[N];
bool vis[N],vise[N];
int main() {
	scanf("%d%d%d",&n,&m,&k);
	if (k==1) {
		euler::init(n);
	}
	rep(i,1,m+1) {
		int u,v;
		scanf("%d%d",&u,&v);
		--u; --v;
		e[u].pb(mp(v,i));
		e[v].pb(mp(u,i));
		E[i]=mp(u,v);
		deg[u]++; deg[v]++;
		if (k==1) {
			euler::add(u,v,i);
			euler::add(v,u,-i);
		}
	}
	if (k==1) {
		VI odd;
		rep(i,0,n) if (deg[i]%2==1) odd.pb(i);
		if (SZ(odd)>=4) { puts("-1"); return 0; }
		if (SZ(odd)>=2&&odd[0]!=0) {
			puts("-1");
			return 0;
		}
		bool ext=0;
		if (SZ(odd)>=2) {
			int u=0,v=odd[1];
			E[m+1]=mp(u,v);
			euler::add(u,v,m+1);
			euler::add(v,u,-(m+1));
			ext=1;
		}
		auto pat=euler::solve();
		//printf("? %d\n",SZ(pat));
		VI pt;
		for (auto x:pat) {
			if (x>0) pt.pb(E[x].se); else pt.pb(E[-x].fi);
		}
		if (ext) {
			rep(i,0,SZ(pt)-1) {
				if ((pt[i]==0&&pt[i+1]==odd[1])||(pt[i+1]==0&&pt[i]==odd[1])) {
					rotate(pt.begin(),pt.begin()+i+1,pt.end());
					break;
				}
			}
			if (pt[0]!=0) reverse(all(pt));
		} else {
			rep(i,0,SZ(pt)) {
				if (pt[i]==0) {
					rotate(pt.begin(),pt.begin()+i,pt.end());
					break;
				}
			}
			pt.pb(0);
		}
		printf("%d\n",SZ(pt));
		for (auto x:pt) printf("%d ",x+1); puts("");
		return 0;
	}
	VI pt; pt.pb(0);
	function<void(int)> dfs=[&](int u) {
		vis[u]=1;
		for (auto [v,id]:e[u]) {
			if (!vis[v]) {
				vise[id]=1;
				pt.pb(v);
				dfs(v);
				pt.pb(u);
			} else if (!vise[id]) {
				vise[id]=1;
				pt.pb(v); pt.pb(u);
			}
		}
	};
	dfs(0);
	for (auto &x:pt) x+=1;
	if (k%2==0) {
		printf("%d\n",m*k+1);
		printf("%d",pt[0]);
		for (int i=1;i<SZ(pt);i+=2) {
			for (int j=0;j<k/2;j++) {
				printf(" %d %d",pt[i],pt[i+1]);
			}
		}
		puts("");
	} else {
		printf("%d\n",m*k+1);
		printf("%d",pt[0]);
		for (int i=1;i<SZ(pt);i+=2) {
			if (i%4==1) {
				for (int j=0;j<k/2;j++) {
					printf(" %d %d",pt[i],pt[i+1]);
				}
				printf(" %d",pt[i]);
			} else {
				printf(" %d",pt[i-1]);
				for (int j=0;j<k/2;j++) {
					printf(" %d %d",pt[i],pt[i+1]);
				}
			}
		}
		puts("");		
	}
}