#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (int i=(int)from; i<(int)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (int i=(int)N-1; i>=0; i--)

const ll MOD = pow(10,9)+7;
const ll LLINF = pow(2,63)-1;
const int INF = pow(2,30)-1;

vector<ll> fac;
void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; }
ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; }
ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; }
ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }

int main() {
  ll N, M, K; cin >> N >> M >> K;
  ll c[N] = {}; rep(i,N) c[i] = i==0 ? 0 : c[i-1]*2+1;
  vector<vector<ll>> d(N); rep(i,N) d[i].resize(N,LLINF);
  rep(i,N) d[i][i] = 0;
  rep(i,M) {
    ll U, V; cin >> U >> V; U--; V--;
    d[U][V] = 1; d[V][U] = 1;
  }
  rep(k,N) rep(i,N) rep(j,N) d[i][j] = min(d[i][j], d[i][k]+d[k][j]);
  // debug(c,c+N); rep(i,N) debug(all(d[i]));

  vector<ll> use = {0}; ll l = 1;
  per(x,N) {
    if (x==0) break;
    ll dp[1<<l+1][l+1] = {}; rep(i,1<<l+1) fill_n(dp[i],l+1,LLINF);
    dp[1][0] = 0;
    rep(k,1<<l+1) rep(i,l+1) rep(j,l+1) {
      ll from = i==l ? x : use[i];
      ll to = j==l ? x : use[j];
      if ( i!=j && ((1<<i)&k) && ((1<<j)&k) ) {
        // cout << k << "-" << from << "," << to << endl;
        dp[k][j] = min(dp[k][j], dp[k^(1<<j)][i] + d[from][to]);
      }
    }
    bool ok = false; rep(i,l+1) ok |= dp[(1<<l+1)-1][i]<=K;
    if (ok) { use.push_back(x); l++; }
    // rep(i,l+1) cout << dp[(1<<l+1)-1][i] << " "; cout << endl;
  }
  // debug(all(use));

  ll result = 0; for (auto x: use) result += c[x];
  cout << result << endl;
  return 0;
}