#include <bits/stdc++.h>
using namespace std;
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)
#define ALL(c) (c).begin(), (c).end()
#define valid(y,x,h,w) (0<=y&&y<h&&0<=x&&x<w)
#define tpl(...) make_tuple(__VA_ARGS__)
const int INF = 0x3f3f3f3f;
const double EPS = 1e-8;
const double PI = acos(-1);
typedef long long ll;
typedef pair<int,int> pii;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
template<class T>ostream&operator<<(ostream &o,const vector<T>&t){o<<'[';FOR(i,t){if(i!=t.begin())o<<',';o<<*i;}return o<<']';}
template<class S,class T>ostream&operator<<(ostream &o,const pair<S,T>&t){return o<<'('<<t.first<<','<<t.second<<')';}
template<int N,class Tp>void output(ostream&,const Tp&){}
template<int N,class Tp,class,class ...Ts>void output(ostream &o,const Tp&t){if(N)o<<',';o<<get<N>(t);output<N+1,Tp,Ts...>(o,t);}
template<class ...Ts>ostream&operator<<(ostream&o,const tuple<Ts...>&t){o<<'(';output<0,tuple<Ts...>,Ts...>(o,t);return o<<')';}
template<class T>void output(T t,char z=10){if(t<0)t=-t,putchar(45);int c[20];
int k=0;while(t)c[k++]=t%10,t/=10;for(k||(c[k++]=0);k;)putchar(c[--k]^48);putchar(z);}
template<class T>void outputs(T t){output(t);}
template<class S,class ...T>void outputs(S a,T...t){output(a,32);outputs(t...);}
template<class T>void output(T *a,int n){REP(i,n)cout<<a[i]<<(i!=n-1?',':'\n');}
template<class T>void output(T *a,int n,int m){REP(i,n)output(a[i],m);}
template<class T>bool input(T &t){int n=1,c;for(t=0;!isdigit(c=getchar())&&~c&&c-45;);
if(!~c)return 0;for(c-45&&(n=0,t=c^48);isdigit(c=getchar());)t=10*t+c-48;t=n?-t:t;return 1;}
template<class S,class ...T>bool input(S&a,T&...t){input(a);return input(t...);}
template<class T>bool inputs(T *a, int n) { REP(i,n) if(!input(a[i])) return 0; return 1;}

int g[60][60];
int dp[1<<17][17];
int main() {
  int n,m,k;
  while(input(n,m,k)) {
    REP(i,n) {
      REP(j,n) g[i][j] = INF;
      g[i][i] = 0;
    }
    REP(i,m) {
      int u,v;
      input(u,v);
      u--;v--;
      g[u][v] = g[v][u] = 1;
    }
    REP(k,n) REP(i,n)REP(j,n) chmin(g[i][j], g[i][k]+g[k][j]);
    vector<int> ans({0});
    for (int i=n-1; i>0; --i) {
      vector<int> tmp(ans);
      tmp.push_back(i);
      int N = tmp.size();
      REP(S,1<<N)REP(i,N)dp[S][i] = INF;
      dp[1<<0][0] = 0;
      REP(S,1<<N) {
        REP(i,N) {
          if (S>>i&1) {
            if (dp[S][i] == INF) continue;
            REP(j,N) {
              if (S>>j&1) continue;
              chmin(dp[S|1<<j][j], dp[S][i] + g[tmp[i]][tmp[j]]);
            }
          }
        }
      }
      bool ok = 0;
      REP(i,N) {
        if (dp[(1<<N)-1][i] <= k) ok = 1;
      }
      if (ok) {
        ans = tmp;
      }
    }
    ll res = 0;
    REP(i,ans.size()) {
      ll tmp = 1;
      REP(j,ans[i]) tmp *= 2;
      res += tmp - 1;
    }
    cout << res << endl;
  }
}