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

#ifdef DEBUG
#define fast
#else
#define fast cin.tie(0)->sync_with_stdio(0)
#define endl '\n'
#define cerr if(1);else cerr
#endif
#define _ <<' '<<
#define ALL(v) v.begin(),v.end()
#define ft first
#define sd second

using ll = long long;
using ld = long double;
using pii = pair<int,int>;

const int MAXN = 100005;
vector<int> G[MAXN];
bool black[MAXN];
int ans = 0;
int K ;

int dfs(int cur, int fa) {
    int cnt_black = (black[cur] == 1);
    int sum_black = (black[cur] == 1);
    for (int &nxt : G[cur]) {
        if (nxt == fa) continue;
        int sz = dfs(nxt, cur);
        cnt_black += sz > 0;
        sum_black += sz;
    }
    if (K - sum_black > 0) cnt_black++;

    if (black[cur] || cnt_black >= 2) {
        ++ans;
    }
    return sum_black;
}

signed main() {
    fast;
    int n, k;
    cin >> n >> k ;
    K = k;

    for (int i = 1; i < n; ++i) {
        int a, b, w;
        cin >> a >> b >> w;
        G[a].push_back(b);
        G[b].push_back(a);
    }

    for (int i = 0; i < k; ++i) {
        int x; cin >> x;
        black[x] = 1;
    }
    
    dfs(1,1);

    cout << ans <<  endl;

    return 0;
}