#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[8]={-1,0,1,0,1,1,-1,-1};
const ll dx[8]={0,-1,0,1,1,-1,1,-1};
template <typename T> inline bool chmax(T &a, T b) {
  return ((a < b) ? (a = b, true) : (false));
}
template <typename T> inline bool chmin(T &a, T b) {
  return ((a > b) ? (a = b, true) : (false));
}
ll n,m,k;
vvl mat(60,vl(60,INF));
vl id;
ll x;
vvl TSP(){
  x=id.size();
  vvl dp(1<<x,vl(x,inf));
  rep(i,x)dp[1<<i][i]=mat[0][id[i]];
  rep(bit,1<<x){
    rep(i,x){
      if(bit&(1<<i)){
        rep(to,x){
          if(bit&(1<<to))continue;
          chmin(dp[bit|(1<<to)][to],dp[bit][i]+mat[id[i]][id[to]]);
        }
      }
    }
  }
  return dp;
}
int main(){
  cin >> n >> m >> k;
  rep(i,m){
    ll u,v;cin >> u >> v;u--;v--;
    mat[u][v]=1;mat[v][u]=1;
  }
  rep(i,n)mat[i][i]=0;
  rep(k,n)rep(i,n)rep(j,n)chmin(mat[i][j],mat[i][k]+mat[k][j]);
  per(i,n){
    id.emplace_back(i);
    auto dp=TSP();
    ll ans=inf;
    rep(j,x)chmin(ans,dp[(1<<x)-1][j]);
    if(ans>k)id.pop_back();
  }
  ll ans=0;
  for(auto p:id){
    ans+=(1LL<<p)-1;
  }
  cout << ans <<endl;
}