#include <bits/stdc++.h>

using namespace std;

#define pr pair<int, int>

#define mp make_pair

const int maxn = 2000003;

const int inf = 1000000000;

void setIO(string a)

{

    string in = a + ".in", out = a + ".out";

    freopen(in.c_str(), "r", stdin);

}

vector <pr> vrr;

int edges, n, m, K, ans, mdep, tl, root = 0, sn;

int hd[maxn], to[maxn << 1], nex[maxn << 1], val[maxn << 1], siz[maxn];

int mk[maxn],  vis[maxn], mine[maxn], dis[maxn], tmp1[maxn], tmp2[maxn], f[maxn];

void add(int u, int v, int c)

{

    nex[++edges] = hd[u], hd[u] = edges, to[edges] = v, val[edges] = c;

}

void Getroot(int u, int ff)

{

    siz[u] = 1, f[u] = 0;

    for(int i = hd[u]; i ; i = nex[i])

    {

        int v = to[i];

        if(v == ff || vis[v]) continue;

        Getroot(v, u);

        siz[u] += siz[v], f[u] = max(f[u], siz[v]);

    }

    f[u] = max(sn - siz[u], f[u]);

    if(f[u] < f[root]) root = u;

}

void getmax(int x, int ff, int d1)

{

    siz[x]=1;

    mdep = max(mdep, d1 + mk[x]);

    for(int i = hd[x]; i ; i = nex[i])

    {

        int v = to[i];

        if(vis[v] || v == ff) continue;

        dis[v] = dis[x] + val[i];

        getmax(v, x, d1 + mk[x]);

        siz[x]+=siz[v];

    }

}

void getdis(int x, int ff, int d2)

{

    if(d2 > K) return ;

    tmp1[++tl] = dis[x], tmp2[tl] = d2 + mk[x];

    for(int i = hd[x]; i ; i = nex[i])

    {

        int v = to[i];

        if(v == ff || vis[v]) continue;

        getdis(v, x, d2 + mk[x]);

    }

}

void calc(int x)

{

    if(mk[x]) --K;

    vrr.clear();

    siz[x]=1;

    for(int i = hd[x]; i ; i = nex[i])

    {

        int v = to[i];

        if(vis[v]) continue;

        mdep = 0, dis[v] = val[i];

        getmax(v, x, 0);

        siz[x]+=siz[v];

        vrr.push_back(mp(mdep, v));

    }

    sort(vrr.begin(), vrr.end());

    tl = mine[0] = 0;

   //  printf("%d ::: ",x);

    for(int sz = vrr.size(), i = 0; i < sz; ++i)

    {

        int cur = vrr[i].second;

        int pdl = tl;

        getdis(cur, x, 0);

        for(int j = pdl + 1; j <= tl; ++j)

            if(K >= tmp2[j])

                ans = max(ans, mine[K - tmp2[j]] + tmp1[j]);

        // printf("%d ",vrr[i].second);

        // tmp2[j] :: 有tmp2[j]个黑子时的最大值.

        for(int j = pdl + 1; j <= tl; ++j) mine[tmp2[j]] = max(mine[tmp2[j]], tmp1[j]);

        for(int j = 1; j <= vrr[i].first; ++j) mine[j] = max(mine[j-1],mine[j]);

    }

    // printf("\n");

    if(vrr.size())

        for(int i=1;i<=vrr[vrr.size()-1].first;++i) mine[i] = -inf;

    if(mk[x]) ++K;

}

void solve(int u)

{

    vis[u] = 1;

    calc(u);

    for(int i=hd[u];i;i=nex[i])

    {

        int v=to[i];

        if(vis[v]) continue;

        root=0,sn=siz[v];

        Getroot(v,u);

        solve(root);

    }

}

int main()

{

   //  setIO("input");

    scanf("%d%d%d",&n, &K, &m);

    for(int i = 1,o; i <= m ; ++i)

    {

        scanf("%d",&o);

        mk[o] = 1;

    }

    for(int i = 1; i < n ; ++i)

    {

        int u, v, c;

        scanf("%d%d%d",&u, &v, &c);

        add(u, v, c), add(v, u, c);

    }

    for(int i=1;i<maxn;++i) mine[i]=-inf;

    sn = n, f[0] = inf;

    Getroot(1, 0); solve(root);

    printf("%d\n",ans);

    return 0;

}