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

#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

#define mygc(c) (c)=getchar_unlocked()
#define mypc(c) putchar_unlocked(c)

#define ll long long

void reader(int *x){int k,m=0;*x=0;for(;;){mygc(k);if(k=='-'){m=1;break;}if('0'<=k&&k<='9'){*x=k-'0';break;}}for(;;){mygc(k);if(k<'0'||k>'9')break;*x=(*x)*10+k-'0';}if(m)(*x)=-(*x);}
void reader(int *x, int *y){reader(x);reader(y);}
void reader(int *x, int *y, int *z){reader(x);reader(y);reader(z);}
void writer(int x, char c){int i,sz=0,m=0;char buf[10];if(x<0)m=1,x=-x;while(x)buf[sz++]=x%10,x/=10;if(!sz)buf[sz++]=0;if(m)mypc('-');while(sz--)mypc(buf[sz]+'0');mypc(c);}
void writer(ll x, char c){int i,sz=0,m=0;char buf[20];if(x<0)m=1,x=-x;while(x)buf[sz++]=x%10,x/=10;if(!sz)buf[sz++]=0;if(m)mypc('-');while(sz--)mypc(buf[sz]+'0');mypc(c);}

#define INF 1000000000

int N, M, K;
int edge[111][111], es[111];

ll coins[111];
int dist[111][111];

int ok[20], oks;
int dp[66666][17];

int main(){
  int i, j, k, st;
  ll res;

  reader(&N,&M,&K);
  assert(1 <= N && N <= 60);
  assert(0 <= K && K <= 15);

  rep(i,N) coins[i] = (1LL << i) - 1;

  rep(i,N) rep(j,N) dist[i][j] = INF;
  rep(i,N) dist[i][i] = 0;
  while(M--){
    reader(&i,&j);
    assert(1 <= i && i <= N);
    assert(1 <= j && j <= N);
    i--; j--;
    assert(dist[i][j]==INF);
    dist[i][j] = dist[j][i] = 1;
  }

  rep(k,N) rep(i,N) rep(j,N) dist[i][j] = min(dist[i][j], dist[i][k]+dist[k][j]);

  ok[0] = 0;
  oks = 1;
  for(st=N-1;st;st--){
    if(oks==K+1) continue;
    ok[oks++] = st;

    rep(i,1<<oks) rep(j,oks) dp[i][j] = INF;
    dp[1<<0][0] = 0;
    rep(i,1<<oks) rep(j,oks) if(dp[i][j] != INF) rep(k,oks) if(!(i&1<<k)){
      dp[i|(1<<k)][k] = min(dp[i|(1<<k)][k], dp[i][j] + dist[ok[j]][ok[k]]);
    }

    rep(k,oks) if(dp[(1<<oks)-1][k] <= K) break;
    if(k==oks) oks--;
  }

  res = 0;
  rep(i,oks) res += coins[ok[i]];
  writer(res, '\n');

  return 0;
}