#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
using namespace std;

const int INF = INT_MAX / 4;

void shortestPath(const vector<vector<int> >& edges, int start, vector<int>& dist)
{
    int n = edges.size();
    dist.assign(n, INF);
    dist[start] = 0;
    queue<int> q;
    q.push(start);

    while(!q.empty()){
        int v = q.front();
        q.pop();
        for(unsigned i=0; i<edges[v].size(); ++i){
            int u = edges[v][i];
            if(dist[u] == INF){
                dist[u] = dist[v] + 1;
                q.push(u);
            }
        }
    }
}

void shortestPath(const vector<vector<int> >& edges, vector<vector<int> >& dist)
{
    dist.resize(edges.size());
    for(unsigned i=0; i<edges.size(); ++i)
        shortestPath(edges, i, dist[i]);
}

int solve(const vector<vector<int> >& dist, const vector<int> node)
{
    int n = node.size();
    vector<vector<int> > dp(1<<n, vector<int>(n, INF));
    for(int i=0; i<n; ++i)
        dp[1<<i][i] = dist[0][node[i]];

    for(int i=0; i<(1<<n); ++i){
        bitset<32> bs(i);
        for(int j=0; j<n; ++j){
            if(!bs[j])
                continue;
            for(int k=0; k<n; ++k){
                if(bs[k])
                    continue;

                bs[k] = true;
                dp[bs.to_ulong()][k] = min(dp[bs.to_ulong()][k], dp[i][j] + dist[node[j]][node[k]]);
                bs[k] = false;
            }
        }
    }

    return *min_element(dp.back().begin(), dp.back().end());
}

int main()
{
    int n, m, k;
    cin >> n >> m >> k;
    vector<vector<int> > edges(n);
    for(int i=0; i<m; ++i){
        int a, b;
        cin >> a >> b;
        edges[a-1].push_back(b-1);
        edges[b-1].push_back(a-1);
    }

    vector<vector<int> > dist;
    shortestPath(edges, dist);

    long long ret = 0;
    vector<int> node;
    for(int i=n-1; i>0; --i){
        node.push_back(i);
        if(solve(dist, node) <= k)
            ret += (1LL << i) - 1;
        else
            node.pop_back();
    }
    cout << ret << endl;

    return 0;
}