#include <bits/stdc++.h>
using namespace std;

#define int long long

signed main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int N,M,K;
	cin>>N>>M>>K;
	vector<vector<int>>g(N+1),t(N+1);
	vector<pair<int,int>>e;
	for(int i=0;i<M;i++){
		int a,b;
		cin>>a>>b;
		if(i<K){
			t[a].push_back(b);
			t[b].push_back(a);
			e.emplace_back(a,b);
			e.emplace_back(b,a);
		}
		else{
			g[a].push_back(b);
			g[b].push_back(a);
		}
	}
	if(0){
start:
		int TREE=0;
		N=2+rand()%10,M=TREE?N-1:rand()%min(N*(N-1)/2,N*2),K=M==0?0:rand()%M;
		struct DSU {
			vector<int> v;

			DSU(int n) : v(n + 1, -1) {
			}

			int find(int a) {
				return v[a] < 0 ? a : v[a] = find(v[a]);
			}

			void unite(int a, int b) {
				a = find(a);
				b = find(b);
				if (a == b) {
					return;
				}
				if (v[a] > v[b]) {
					swap(a, b);
				}
				v[a] += v[b];
				v[b] = a;
			}
		};
		DSU dsu(N+1);
		g.clear();
		g.resize(N+1);
		t.clear();
		t.resize(N+1);
		e.clear();
		set<pair<int,int>>s;
		for(int i=0;i<M;i++){
			int a,b;
			do{
				a=1+rand()%N,b=1+rand()%N;
			}
			while(a==b||s.count({a,b})||(TREE&&dsu.find(a)==dsu.find(b)));
			s.insert({a,b});
			s.insert({b,a});
			dsu.unite(a,b);
			if(i<K){
				t[a].push_back(b);
				t[b].push_back(a);
				e.emplace_back(a,b);
				e.emplace_back(b,a);
			}
			else{
				g[a].push_back(b);
				g[b].push_back(a);
			}
		}
	}
	vector<vector<pair<int,int>>>gg(N+1);
	for(int i=1;i<=N;i++){
		for(int j:g[i]){
			gg[i].emplace_back(j,0);
		}
		for(int j:t[i]){
			gg[i].emplace_back(j,1);
		}
	}
#define g gg
	vector<int>v(N+1),w(N+1),u(N+1),p(N+1),ti(N+1),to(N+1);
	vector<array<int,16>>up(N+1);
	auto des=[&](int a,int b)->bool{
		return ti[a]<=ti[b]&&to[a]>=to[b];
	};
	auto lca=[&](int a,int b)->int{
		while(!des(a,b)){
			for(int i=1;;i++){
				if(des(up[a][i],b)){
					a=up[a][i-1];
					break;
				}
			}
		}
		return a;
	};
	auto lcb=[&](int a,int b)->int{
		if(des(a,b)){
			return -1;
		}
		while(!des(p[a],b)){
			for(int i=1;;i++){
				if(des(p[up[a][i]],b)){
					a=up[a][i-1];
					break;
				}
			}
		}
		return a;
	};
	int ta=1;
	auto dfs=[&](auto self,int i)->void{
		w[i]=i;
		up[i][0]=p[i];
		for(int j=1;j<16;j++){
			up[i][j]=up[up[i][j-1]][j-1];
		}
		ti[i]=ta++;
		for(auto[j,b]:g[i]){
			if(v[j]){
				if(v[j]<v[w[i]]){
					w[i]=j;
				}
				continue;
			}
			v[j]=v[i]+1;
			p[j]=i;
			self(self,j);
			if(v[w[j]]<v[w[i]]){
				w[i]=w[j];
			}
		}
		to[i]=ta++;
	};
	v[1]=1;
	dfs(dfs,1);
	ti[0]=0;
	to[0]=ta;
	auto dfs2=[&](auto self,int i)->void{
		for(auto[j,b]:g[i]){
			if(j==p[i]){
				continue;
			}
			if(v[j]>v[i]+1){
				continue;
			}
			if(v[j]<v[i]){
				continue;
			}
			if(b){
				u[j]=1;
			}
			self(self,j);
		}
	};
	dfs2(dfs2,1);
	auto dfs3=[&](auto self,int i,int b)->void{
		u[i]|=b;
		b|=u[i];
		for(auto[j,x]:g[i]){
			if(v[j]&&p[j]!=i){
				continue;
			}
			v[j]=v[i]+1;
			p[j]=i;
			self(self,j,b|x);
		}
	};
	dfs3(dfs3,1,0);
#undef g
	if(0){
		int st=clock();
		vector<int>ans;
		for(int i=1;i<=N;i++){
			if(u[i])ans.push_back(i);
		}
		vector<int>v(N+1),u(N+1);
		auto bt=[&](auto self,int i,int b)->void{
			if(clock()>st+CLOCKS_PER_SEC/10){
				return;
			}
			if(v[i]){
				return;
			}
			if(b){
				u[i]=1;
			}
			v[i]=1;
			for(int j:g[i]){
				self(self,j,b);
			}
			for(int j:t[i]){
				self(self,j,1);
			}
			v[i]=0;
		};
		bt(bt,1,0);
		if(clock()>st+CLOCKS_PER_SEC/10){
			cout<<"TIMEOUT"<<endl;
			goto start;
		}
		vector<int>ans1;
		for(int i=1;i<=N;i++){
			if(u[i]){
				ans1.push_back(i);
			}
		}
		if(ans1.size()!=ans.size()){
			for(int i=1;i<=N;i++){
				for(int j:g[i]){
					if(j<i)continue;
					cout<<i<<' '<<j<<' '<<0<<endl;
				}
				for(int j:t[i]){
					if(j<i)continue;
					cout<<i<<' '<<j<<' '<<1<<endl;
				}
			}
			cout<<"============= GOT ============="<<endl;
			cout<<ans.size()<<'\n';
			for(int i:ans){
				cout<<i<<' ';
			}
			cout<<'\n';
			cout<<"============= EXP ============="<<endl;
			cout<<ans1.size()<<'\n';
			for(int i:ans1){
				cout<<i<<' ';
			}
			cout<<'\n';
			exit(1);
		}
		static int cc=0;
		cout<<"OK "<<setw(9)<<cc++<<" "<<ans.size()<<endl;
		goto start;
	}
	cout<<count(u.begin(),u.end(),1)<<'\n';
	for(int i=1;i<=N;i++){
		if(u[i]){
			cout<<i<<' ';
		}
	}
	cout<<'\n';
	return 0;
}