#include "bits/stdc++.h"
using namespace std;

#define MAX 9999999

int dp[(1 << 16)][16];
int dist[60][60];

void warshall(int N){
	for (int k = 0; k < N; k++)
	{
		for (int i = 0; i < N; i++)
		{
			for (int j = 0; j < N; j++)
			{
				dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
			}
		}
	}
}

int bitDP(vector<int>& v, int M){
	int N = v.size();
	for (int i = 0; i < (1 << N); i++)
	{
		for (int j = 0; j < N; j++)
		{
			dp[i][j] = MAX;
		}
	}
	for (int i = 0; i < N; i++)
	{
		dp[1 << i][i] = dist[0][v[i]];
	}

	for (int i = 0; i < (1<<N); i++)
	{
		for (int j = 0; j < N; j++)
		{
			if (dp[i][j] == MAX) continue;
			for (int k = 0; k < N; k++)
			{
				if ((i >> k) % 2 == 1) continue;
				int next = dp[i][j] + dist[v[j]][v[k]];
				int nexti = i + (1 << k);
				dp[nexti][k] = min(dp[nexti][k], next);
			}
		}
	}
	int ans = MAX;
	for (int i = 0; i < N; i++)
	{
		ans = min(ans, dp[(1 << N) - 1][i]);
	}
	return ans;
}

int main(){
	int N, M, K;
	cin >> N >> M >> K;
	vector<int> v;
	for (int i = 0; i < N; i++)
	{
		for (int j = 0; j < N; j++)
		{
			dist[i][j] = MAX;
		}
		dist[i][i] = 0;
	}

	for (int i = 0; i < M; i++)
	{
		int U, V;
		cin >> U >> V;
		U--; V--;
		dist[U][V] = dist[V][U] = 1;
	}
	warshall(N);

	long long ans = 0;
	for (int i = N - 1; i >= 1 && v.size() < K; i--)
	{
		v.push_back(i);
		int cost = bitDP(v, N);
		if (cost > K){
			v.pop_back();
		}
		else{
			ans += (1ll << i) - 1;
		}
	}
	cout << ans << endl;

}