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#include <algorithm>
#include <cassert>
#include <cctype>
#include <unistd.h>
#include <utility>
#include <vector>
using namespace std;

class Input {
 public:
  Input() { bufpos = bufend = buffer; eof = false; }
  bool Eof() { return eof; }
  char Peek() { if(bufpos == bufend) Grab(); return *bufpos; }
  unsigned char UPeek() { return static_cast<unsigned char>(Peek()); }
  void SkipWS();
  template<class T> T Get();
  void operator()() {}
  template<class Arg, class... Args> void operator()(Arg &arg, Args &... args) {
    arg = Get<Arg>();
    operator()(args...);
  }
 private:
  static const int BUFSIZE = 1<<16;
  char buffer[BUFSIZE];
  char *bufpos;
  char *bufend;
  bool eof;
  void Grab();
};

void Input::Grab() {
  if(eof) return;
  bufpos = buffer;
  bufend = buffer + read(0, buffer, BUFSIZE);
  if(bufend==bufpos) { eof=true; *bufpos=0; }
}

template<> inline char Input::Get<char>() {
  char res = Peek();
  ++bufpos;
  return res;
}

void Input::SkipWS() {
  while(isspace(UPeek())) Get<char>();
}

template<> unsigned Input::Get<unsigned>() {
  SkipWS();
  unsigned x = 0;
  while(isdigit(UPeek())) {
    x = 10u * x + (Get<char>()-'0');
  }
  return x;
}

template<> int Input::Get<int>() {
  SkipWS();
  bool neg = false;
  if(Peek()=='-') { neg=true; Get<char>(); }
  unsigned x = Get<unsigned>();
  if (neg) x = -x;
  return static_cast<int>(x);
}

class Output {
 public:
  void Flush();
  Output():bufpos(buffer),BUFLIMIT(buffer+BUFSIZE-100) {}
  ~Output() { Flush(); }
  void Put(char c);
  void Put(unsigned x);
  void Put(int x);
  void Put(const char*s);

  void operator()() {}
  template<class Arg, class... Args> void operator()(const Arg &arg, const Args &... args) {
    Put(arg);
    operator()(args...);
  }
 private:
  static const int BUFSIZE = 1<<16;
  char buffer[BUFSIZE];
  char *bufpos;
  char *BUFLIMIT;
};

void Output::Flush() {
  char *p = buffer;
  while(p < bufpos) {
    p += write(1, p, bufpos-p);
  }
  bufpos = buffer;
}

inline void Output::Put(char c) {
  *bufpos = c;
  ++bufpos;
  if(bufpos >= BUFLIMIT) Flush();
}

void Output::Put(unsigned x) {
  char *old = bufpos;
  do {
    *bufpos = char('0' + x % 10u);
    x /= 10u;
    ++bufpos;
  } while(x);
  reverse(old, bufpos);
  if(bufpos >= BUFLIMIT) Flush();
}

void Output::Put(int x) {
  if(x<0) {
    Put('-'); Put(-static_cast<unsigned>(x));
  } else {
    Put(static_cast<unsigned>(x));
  }
}

void Output::Put(const char*s) {
  while(*s) Put(*s++);
}

Input IN;
Output OUT;

// --------------

const int COMPONENT_NONE = -1;
const int COMPONENT_KILLED = -2;

struct Node {
  int degree;
  Node **neighbors;
  int component;

  Node() : degree{0}, neighbors{nullptr}, component{COMPONENT_NONE} {}
};

vector<Node> nodes; // contains killed sentinel
vector<pair<Node*,Node*>> edges;
int minDegree;
vector<Node*> neighborStorage;

void ReadInput() {
  int n, m;
  IN(n, m, minDegree);
  nodes.resize(n+1);
  nodes[n].component = COMPONENT_KILLED;
  edges.resize(m);
  for (auto &e : edges) {
    int a, b;
    IN(a, b);
    e.first = &nodes[a-1];
    e.second = &nodes[b-1];
    ++e.first->degree;
    ++e.second->degree;
  }
}

void ComputeNeighbors() {
  neighborStorage.resize(2 * edges.size());

  // Prepare to fill backwards.
  Node **nextStorage = &neighborStorage[0];;
  for (Node &node : nodes) {
    nextStorage += node.degree;
    node.neighbors = nextStorage;
  }
  assert(nextStorage == &neighborStorage[0] + neighborStorage.size());

  // Fill.
  for (const auto &e : edges) {
    *(--e.first->neighbors) = e.second;
    *(--e.second->neighbors) = e.first;
  }
}

void KillSmallDegrees() {
  vector<Node*> killStack;
  killStack.reserve(nodes.size());
  for (Node &node : nodes) {
    if (node.component == COMPONENT_KILLED) continue;
    if (node.degree < minDegree) killStack.push_back(&node);
  }
  while (!killStack.empty()) {
    Node *const node = killStack.back();
    killStack.pop_back();
    node->component = COMPONENT_KILLED;
    Node *const *const endNeighbors = (node+1)->neighbors;
    for (Node *const *p = node->neighbors; p != endNeighbors; ++p) {
      Node *const x = *p;
      if (x->degree == minDegree) killStack.push_back(x);
      --x->degree;
    }
  }
}

int Dfs(Node *const start, const int component, vector<Node*> &dfsStack) {
  start->component = component;
  dfsStack.push_back(start);
  int res = 1;

  while (!dfsStack.empty()) {
    Node *const node = dfsStack.back();
    dfsStack.pop_back();

    Node *const *const endNeighbors = (node+1)->neighbors;
    for (Node *const *p = node->neighbors; p != endNeighbors; ++p) {
      Node *const x = *p;
      if (x->component == COMPONENT_NONE) {
        x->component = component;
        dfsStack.push_back(x);
        ++res;
      }
    }
  }

  return res;
}

void LargestComponent(int &largestComponent, int &largestSize) {
  largestComponent = COMPONENT_NONE;
  largestSize = 0;

  vector<Node*> dfsStack;
  dfsStack.reserve(nodes.size());
  int nextComponent = 0;
  for (Node &node : nodes) {
    if (node.component == COMPONENT_NONE) {
      const int size = Dfs(&node, nextComponent, dfsStack);
      if (size > largestSize) {
        largestComponent = nextComponent;
        largestSize = size;
      }
      ++nextComponent;
    }
  }
}

void PrintComponent(int component, int size) {
  if (component == COMPONENT_NONE) {
    OUT("NIE\n");
  } else {
    OUT(size, '\n');
    for (const Node &x : nodes) {
      if (x.component == component) {
        const int id = &x - &nodes[0] + 1;
        OUT(id, ' ');
      }
    }
    OUT('\n');
  }
}

int main() {
  ReadInput();
  ComputeNeighbors();
  KillSmallDegrees();
  int largestComponent, largestSize;
  LargestComponent(largestComponent, largestSize);
  PrintComponent(largestComponent, largestSize);
}