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

int main(){
    int N, K;
    cin >> N >> K;
    vector<int> edges[100000];
    for(int i=0; i<N-1; i++){
        int a, b;
        cin >> a >> b;
        edges[a-1].push_back(b-1);
        edges[b-1].push_back(a-1);
    }
    if(N < K){
        cout << -1 << endl;
        return 0;
    }
    vector<int> dist(N);
    auto dfs = [&](auto&& dfs, int i, int p)->void{
        for(int j : edges[i]) if(j != p){
            dist[j] = dist[i] + 1;
            dfs(dfs, j, i);
        }
    };
    dfs(dfs, 0, -1);
    sort(dist.begin(), dist.end());
    int64_t ans = 0;
    for(int i=0; i<K; i++) ans += dist[i];
    cout << ans << endl;
    return 0;
}