#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T next_num() {
  T i = 0;
  char c;
  while (!isdigit(c = getchar()) && c != '-')
    ;
  bool flag = c == '-';
  flag ? (c = getchar()) : 0;
  while (i = i * 10 - '0' + c, isdigit(c = getchar()))
    ;
  return flag ? -i : i;
}
template <class T1, class T2>
inline void apmax(T1 &a, const T2 &b) {
  if (a < b) a = b;
}
template <class T1, class T2>
inline void apmin(T1 &a, const T2 &b) {
  if (b < a) a = b;
}
const int N = 55, INF = 0x7f7f7f7f;
namespace T {
const int E = N << 1;
int to[E], bro[E], val[E], head[N], e = 0;
int f[E][N][N], ccnt[N];
inline void init() {
  memset(head, -1, sizeof(head));
  memset(f, -1, sizeof(f));
  memset(ccnt, 0, sizeof(ccnt));
}
inline void ae(int u, int v, int w) {
  to[e] = v, bro[e] = head[u], val[e] = w, head[u] = e++;
}
inline void add(int u, int v, int w) { ae(u, v, w), ae(v, u, w); }
int tmp[E][N][N][N];
int F(int e, int in, int out) {
  if (~f[e][in][out]) {
    return f[e][in][out];
  }
  int &ans = f[e][in][out];
  if (bro[head[to[e]]] == -1) {
    return ans = out ? F(e ^ 1, out, 0) + val[e] : 0;
  }
  assert(in);
  int *g = tmp[e][in][out];
  g[0] = INF;
  memset(g + 1, 0, in << 2);
  for (int i = head[to[e]]; ~i; i = bro[i]) {
    if (i ^ e ^ 1) {
      for (int j = in; j >= 1; j--) {
        for (int k = 1; k <= j; k++) {
          apmax(g[j], min(g[j - k], F(i, k, in + out - k) + val[i]));
        }
      }
    }
  }
  return ans = g[in];
}
void dfs(int x, int fa) {
  for (int i = head[x], v; ~i; i = bro[i]) {
    if ((v = to[i]) != fa) {
      dfs(v, x);
      ccnt[x] += ccnt[v];
    }
  }
}
}  // namespace T
int main() {
  int n = (next_num<int>());
  T::init();
  for (int i = 1, u, v; i < n; u = (next_num<int>()), v = (next_num<int>()),
           T::add(u, v, (next_num<int>())), i++)
    ;
  int s = (next_num<int>()), m = (next_num<int>());
  for (int i = 1; i <= m; T::ccnt[(next_num<int>())]++, i++)
    ;
  m -= T::ccnt[s];
  T::dfs(s, 0);
  int ans = INF;
  for (int i = T::head[s]; ~i; i = T::bro[i]) {
    using namespace T;
    if (ccnt[to[i]]) {
      apmin(ans, F(i, ccnt[to[i]], m - ccnt[to[i]]) + val[i]);
    }
  }
  printf("%d\n", ans);
  return 0;
}
