#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <climits>
#include <ctime>
#include <cassert>
#include <numeric>
#include <functional>
#include <bitset>

using namespace std;
using lint = long long int;
long long int INF = 1001001001001001LL;
int inf = 1000000007;
long long int MOD = 1000000007LL;
double PI = 3.1415926535897932;

template<typename T1,typename T2>inline void chmin(T1 &a,const T2 &b){if(a>b) a=b;}
template<typename T1,typename T2>inline void chmax(T1 &a,const T2 &b){if(a<b) a=b;}

#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()


// verified : http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=GRL_1_A
// ごめんダイクストラペタリした
template<typename T>
vector<T> dijkstra(vector<vector<pair<int, T>>> &g, int s){
     
  int n = g.size();
  // numeric_limits がうまく使えない場合は自分で INF を定義する.
  const auto inf = numeric_limits<T>::max();
  vector<T> dist(n, inf);

  using P = pair<T, int>;
  // 小さい順に取り出せる
  priority_queue<P, vector<P>, greater<P>> que;
  dist[s] = 0;
  que.emplace(dist[s], s);
  while(!que.empty()){
    T cost;
    int node;
    tie(cost, node) = que.top();
    que.pop();
    if(dist[node] < cost) continue;
    for(auto &e : g[node]){
      auto next_cost = cost + e.second;
      int next_node = e.first;
      if(dist[next_node] <= next_cost) continue;
      dist[next_node] = next_cost;
      que.emplace(next_cost, next_node);
    }
  }

  return dist;
}

/* do your best */

int main() {

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

  if(n < k) {
    cout << -1 << endl;
    return 0;
  }

  auto dist = dijkstra(g, 0);
  sort(ALL(dist));
  int ans = 0;
  for(int i = 0; i < k; i++) ans += dist[i];
  cout << ans << endl;
  return 0;
}