#include"bits/stdc++.h"
using namespace std;
#define REP(k,m,n) for(int (k)=(m);(k)<(n);(k)++)
#define rep(i,n) REP((i),0,(n))
using ll = long long;

int main()
{
    ll N, K;
    cin >> N >> K;
    if (N < K) {
        cout << -1 << endl;
        return 0;
    }
    vector<vector<ll>> edges(N);
    rep(i, N - 1) {
        int a, b;
        cin >> a >> b;
        a--; b--;
        edges[a].push_back(b);
        edges[b].push_back(a);
    }

    vector<ll> d(N, 1 << 20);
    queue<ll> q;
    d[0] = 0;
    q.push(0);
    while (!q.empty()) {
        ll now = q.front(); q.pop();
        for (int next : edges[now])if (d[now] < d[next]) {
            d[next] = d[now] + 1;
            q.push(next);
        }
    }
    sort(d.begin(), d.end());
    cout << accumulate(d.begin(), d.begin() + K, 0ll) << endl;
    return 0;
}