#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v; ll w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-9;

int check(vector<int>& v, vector< vector<int> >& d) {
	int n = v.size();
	vector< vector<int> > dp(1 << n, vector<int>(n, INT_MAX / 2));
	for (int i = 0; i < n; i++)
		dp[1 << i][i] = d[0][v[i]];
	for (int S = 0; S < (1 << n); S++)
		for (int i = 0; i < n; i++) {
			if (!(S & (1 << i))) continue;
			for (int j = 0; j < n; j++) {
				if (S & (1 << j)) continue;
				int _S = S | (1 << j);
				dp[_S][j] = min(dp[_S][j], dp[S][i] + d[v[i]][v[j]]);
			}
		}
	int mini = INT_MAX / 2;
	for (int i = 0; i < n; i++)
		mini = min(mini, dp[(1 << n) - 1][i]);
	return mini;
}

int main() {
	int N, M, K; cin >> N >> M >> K;
	vector< vector<int> > d(N, vector<int>(N, INT_MAX / 2));
	for (int i = 0; i < N; i++) d[i][i] = 0;
	while (M--) {
		int U, V; cin >> U >> V;
		d[U - 1][V - 1] = d[V - 1][U - 1] = 1;
	}
	for (int k = 0; k < N; k++)
		for (int i = 0; i < N; i++)
			for (int j = 0; j < N; j++)
				d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
	vector<bool> a(N);
	vector<int> v;
	ll sum = 0;
	for (;;) {
		bool updated = false;
		for (int i = N - 1; i >= 1; i--) {
			if (a[i]) continue;
			vector<int> _v = v;
			_v.push_back(i);
			if (check(_v, d) <= K) {
				v.push_back(i);
				a[i] = true;
				updated = true;
				sum += (1LL << i) - 1;
				break;
			}
		}
		if (!updated) break;
	}
	cout << sum << endl;
}