#include <iostream>
#include <vector>
#include <queue>
#include <algorithm>
using namespace std;

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

  if (n < k) {
    cout << -1 << endl;
    return 0;
  }
  
  vector<int> dist(n, -1);
  dist[0] = 0;
  queue<int> que;
  que.push(0);
  while(!que.empty()) {
    int v = que.front(); que.pop();
    for (int u : g[v]) {
      if (dist[u] < 0) {
        dist[u] = dist[v] + 1;
        que.push(u);
      }
    }
  }

  sort(dist.begin(), dist.end());
  long long ans = 0;
  for (int i = 1; i < k; i++) {
    ans += dist[i];
  }
  cout << ans << endl;
}