#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n);i++)
#define sz(x) int(x.size())
typedef long long ll;
typedef pair<int,int> P;

int main(){
  int n, k;
  cin >> n >> k;
  vector<vector<int>> g(n);
  rep(i, n-1) {
    int a, b;
    cin >> a >> b;
    a--; b--;
    g[a].emplace_back(b);
    g[b].emplace_back(a);
  }
  if (n < k) {
    cout << -1 << endl;
    return 0;
  }
  vector<int> d(n, 0);
  queue<int> que;
  que.push(0);
  d[0] = 0;
  int res = 0;
  while (!que.empty()) {
    int u = que.front(); que.pop();
    for (auto v : g[u]) {
      if (d[v] != 0) continue;
      d[v] = d[u] + 1;
      que.push(v);
    }
  }
  sort(d.begin(), d.end());
  for (int i = 0; i < k-1;i++) res += d[i];
  cout << res << endl;
  return 0;
}