#ifdef KOMAKI_LOCAL
#include <omp.h>
#else
#define NDEBUG
#endif

#include <bits/stdc++.h>
#include <sys/time.h>
#include <unistd.h>
using namespace std;
#define i64         int64_t
#define rep(i, n)   for(i64 i = 0; i < ((i64)(n)); ++i)
#define sz(v)       ((i64)((v).size()))
#define bit(n)      (((i64)1)<<((i64)(n)))
#define all(v)      (v).begin(), (v).end()

template <int POS, class TUPLE> void deploy(std::ostream &os, const TUPLE &tuple){}
template <int POS, class TUPLE, class H, class ...Ts> void deploy(std::ostream &os, const TUPLE &t){ os << (POS == 0 ? "" : ", ") << get<POS>(t); deploy<POS + 1, TUPLE, Ts...>(os, t); }
template <class ...Ts> std::ostream& operator<<(std::ostream &os, const std::tuple<Ts...> &t){ os << "("; deploy<0, std::tuple<Ts...>, Ts...>(os, t); os << ")"; return os; }
template <class T> std::ostream& operator<<(std::ostream &os, std::vector<T> &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "" : ", "); os << "}"; return os; }
template <class T> std::ostream& operator<<(std::ostream &os, std::set<T> &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "" : ", "); os << "}"; return os; }
template <class T> std::ostream& operator<<(std::ostream &os, std::queue<T> &q){ auto qq = q; os << "{"; for(; !qq.empty(); qq.pop()){ os << qq.front() << (qq.size() != 1 ? ", " : ""); } os << "}"; return os; }
template <class T> std::ostream& operator<<(std::ostream &os, std::priority_queue<T> &q){ auto qq = q; os << "{"; for(; !qq.empty(); qq.pop()){ os << qq.top() << (qq.size() != 1 ? ", " : ""); } os << "}"; return os; }
template <class T, class K> std::ostream& operator<<(std::ostream &os, std::pair<T, K> &p){ os << "(" << p.first << ", " << p.second << ")"; return os; }
template <class T, class K> std::ostream& operator<<(std::ostream &os, std::map<T, K> &mp){ int remain = mp.size(); os << "{"; for(auto e: mp) os << "(" << e.first << " -> " << e.second << ")" << (--remain == 0 ? "" : ", "); os << "}"; return os; }
template <class T, class K> std::ostream& operator<<(std::ostream &os, std::unordered_map<T, K> &mp){ int remain = mp.size(); os << "{"; for(auto e: mp) os << "(" << e.first << " -> " << e.second << ")" << (--remain == 0 ? "" : ", "); os << "}"; return os; }
#define DEBUG0() { char buf[1000]; sprintf(buf, "line:%3d | ", __LINE__); std::cout << buf << std::endl; }
#define DEBUG1(var0) { char buf[1000]; sprintf(buf, "line:%3d | ", __LINE__); std::cout << buf << (#var0) << "=" << (var0) << std::endl; }
#define DEBUG2(var0, var1) { char buf[1000]; sprintf(buf, "line:%3d | ", __LINE__); std::cout << buf << (#var0) << "=" << (var0) << ", " << (#var1) << "=" << (var1) << std::endl; }
#define DEBUG3(var0, var1, var2) { char buf[1000]; sprintf(buf, "line:%3d | ", __LINE__); std::cout << buf << (#var0) << "=" << (var0) << ", " << (#var1) << "=" << (var1) << ", " << (#var2) << "=" << (var2) << std::endl; }
#define DEBUG4(var0, var1, var2, var3) { char buf[1000]; sprintf(buf, "line:%3d | ", __LINE__); std::cout << buf << (#var0) << "=" << (var0) << ", " << (#var1) << "=" << (var1) << ", " << (#var2) << "=" << (var2) << ", " << (#var3) << "=" << (var3) << std::endl; }
#define DEBUG5(var0, var1, var2, var3, var4) { char buf[1000]; sprintf(buf, "line:%3d | ", __LINE__); std::cout << buf << (#var0) << "=" << (var0) << ", " << (#var1) << "=" << (var1) << ", " << (#var2) << "=" << (var2) << ", " << (#var3) << "=" << (var3) << ", " << (#var4) << "=" << (var4) << std::endl; }
#define DEBUG6(var0, var1, var2, var3, var4, var5) { char buf[1000]; sprintf(buf, "line:%3d | ", __LINE__); std::cout << buf << (#var0) << "=" << (var0) << ", " << (#var1) << "=" << (var1) << ", " << (#var2) << "=" << (var2) << ", " << (#var3) << "=" << (var3) << ", " << (#var4) << "=" << (var4) << ", " << (#var5) << "=" << (var5) << std::endl; }













const i64 MAX = 64;
const i64 K = 15;
const i64 BIT_K = bit(K);
int visited[K + 1][K][BIT_K];

int main()
{

  int distances[MAX][MAX];
  rep(i, MAX)rep(j, MAX) distances[i][j] = i == j ? 0 : K + 1;

  i64 n, m, k;
  cin >> n >> m >> k;
  rep(i, m){
    i64 u, v;
    cin >> u >> v;
    distances[u - 1][v - 1] = 1;
    distances[v - 1][u - 1] = 1;
  }
  rep(mid, n)rep(i, n)rep(j, n) distances[i][j] = min(distances[i][j], distances[i][mid] + distances[mid][j]);
  

  i64 best_mask = 0;
  
  for(i64 t = n - 1; 0 <= t && __builtin_popcountll(best_mask) < k; --t){
    i64 next_mask = best_mask | bit(t);

    
    i64 size = 0;
    int terminals[K];
    rep(i, n)if(next_mask & bit(i)) terminals[size++] = i;

    memset(visited, 0, sizeof(visited));
    rep(i, size){
      int d = distances[0][terminals[i]];
      if(d <= K) visited[d][i][bit(i)] = bit(0);
    }

    for(int step = 0; step < k && best_mask != next_mask; ++step){
      for(int tail = 0; tail < size && best_mask != next_mask; ++tail){
        int *v = visited[step][tail];
        for(int mask = 0; mask < bit(size); ++mask){
          if(v[mask] != bit(0)) continue;
          for(int s = step; s <= k; ++s) visited[s][tail][mask] |= bit(1);
          for(int adj = 0; adj < size; ++adj){
            int d = step + distances[terminals[tail]][terminals[adj]];
            if(d <= K){
              visited[d][adj][mask | bit(adj)] |= bit(0);
            }
          }
        }
      }
    }
    for(int step = 0; step <= k; ++step){
      for(int tail = 0; tail < size; ++tail){
        if(visited[step][tail][bit(size) - 1]) best_mask = next_mask;
      }
    }
  }
  i64 ans = 0;
  rep(i, n)if(best_mask & bit(i)) ans += bit(i) - 1;
  cout << ans << endl;
}