#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int N = 5e4 + 10;
int ver[2 * N], nxt[2 * N], head[N], tot;
long long edg[2 * N];
void add(int x, int y, long long z){
	ver[++tot] = y;
	edg[tot] = z;
	nxt[tot] = head[x];
	head[x] = tot;
}
int n, m, a[N];
int f[N][20];
long long dis[N][20];
void dfs1(int x, int fa){
	for(int i = head[x]; i; i = nxt[i]){
		int y = ver[i], z = edg[i];
		if(y == fa)
			continue;
		f[y][0] = x;
		dis[y][0] = z;
		for(int j = 1; j < 20; j++){
			f[y][j] = f[f[y][j-1]][j-1];
			dis[y][j] = dis[y][j-1] + dis[f[y][j-1]][j-1];
		}
		dfs1(y, x);
	}
}
long long tim;
int at, cntc, cntn;
bool ha[N];
struct node{
	int x, y;
	bool us;
}cu[N], need[N];
bool cmp1(node xx, node yy){
	if(xx.x != yy.x)
		return xx.x < yy.x;
	return xx.y < yy.y;
}
bool cmp2(node xx, node yy){
	if(xx.us != yy.us)
		return xx.us < yy.us;
	return xx.y > yy.y;
}
bool dfs2(int x, int fa){
	if(ha[x])
		return 0;
	if(nxt[head[x]] == 0)
		return 1;
	bool res = 0;
	for(int i = head[x]; i; i = nxt[i]){
		int y = ver[i];
		if(y == fa)
			continue;
		res = res | dfs2(y, x);
	}
	return res;
}
bool chk(long long mid){
	memset(ha, 0, sizeof(ha));
	cntc = cntn = 0;
	for(int i = 1; i <= m; i++){
		tim = 0;
		at = a[i];
		for(int j = 19; j >= 0; j--)
			if(tim + dis[at][j] <= mid && f[at][j] > 1){
				tim += dis[at][j];
				at = f[at][j];
			}
		if(f[at][0] == 1 && dis[at][0] + tim < mid)
			cu[++cntc] = (node){at, mid - tim - dis[at][0], 0};
		else
			ha[at] = 1;
	}
	for(int i = head[1]; i; i = nxt[i]){
		int y = ver[i];
		bool fl = dfs2(y, 1);
		if(fl)
			need[++cntn] = (node){y, dis[y][0], 0};
	}
	sort(need + 1, need + cntn + 1, cmp1);
	sort(cu + 1, cu + cntc + 1, cmp1);
	int now = 1;
	if(cntc < cntn)
		return 0;
	for(int i = 1; i <= cntn; i++){
		while(need[i].x > cu[now].x)
			now++;
		if(need[i].x == cu[now].x){
			need[i].us = 1;
			cu[now].us = 1;
			now++;
		}
	}
	sort(need + 1, need + cntn + 1, cmp2);
	sort(cu + 1, cu + cntc + 1, cmp2);
	for(int i = 1; i <= cntn && need[i].us == 0; i++){
		if(cu[i].us == 1)
			return 0;
		if(cu[i].y < need[i].y)
			return 0;
	}
	return 1;
}
int main(){
//	freopen("blockade.in", "r", stdin);
//	freopen("blockade.out", "w", stdout);
	long long l = 0, r = 0;
	scanf("%d", &n);
	for(int i = 1; i <= n - 1; i++){
		int u, v;
		long long w;
		scanf("%d%d%lld", &u, &v, &w);
		add(u, v, w);
		add(v, u, w);
		r += w;
	}
//	cout << r << endl;
	dfs1(1, 0);
	scanf("%d", &m);
	for(int i = 1; i <= m; i++)
		scanf("%d", &a[i]);
	r++;
	long long t = r;
	while(l < r){
		long long mid = (l + r) >> 1;
		if(chk(mid))
			r = mid;
		else
			l = mid + 1;
	}
	if(r == t)
		puts("-1");
	else
		printf("%d\n", l);
	return 0;
}
/*
10
2 1 3
2 3 4
1 4 7
5 1 9
6 1 2
4 7 9
7 8 8
9 8 8
1 10 2
5
2 8 5 4 2 
*/