#include <cstdio>
#include <stack>
#include <vector>
#include <set>

using namespace std;

#define x first
#define y second
#define mp make_pair
#define ii pair<int, int>

const int lg = 100005, inf = 0x3f3f3f3f;

int n, x, y, i, rez, D[lg], val[lg];
bool fst[lg];

vector<int> v[lg], w[lg][2];
stack<int, vector<int> > fiu[lg];
set<ii> q;

int cauta(int nod, int s){
	int cur = 0;

	for (int i = 0; i < (int)w[nod][s].size(); i ++)
		cur += cauta(w[nod][s][i], 0);

	return max(D[nod], cur);
}
void df(int nod){
	fst[nod] = 1;

	set<ii> :: iterator it = q.upper_bound(mp(val[nod], 0));

	if (!fiu[it -> y].size())
		w[it -> y][1].push_back(nod);
	else
		w[ fiu[it -> y].top() ][0].push_back(nod);

	fiu[it -> y].push(nod);

	q.insert( mp(val[nod], nod) );

	for (int i = 0; i < (int)v[nod].size(); i ++)
		if (!fst[ v[nod][i] ])
			df(v[nod][i]);

	q.erase( mp(val[nod], nod) );

	fiu[it -> y].pop();

	D[nod] = cauta(nod, 1) + 1;
}

int main()
{
	freopen("guvern.in", "rt", stdin);
	freopen("guvern.out", "wt", stdout);

	scanf("%d", &n);
	for (i = 1; i < n; i ++){
		scanf("%d%d", &x, &y);

		v[x].push_back(y);
		v[y].push_back(x);
	}
	for (i = 1; i <= n; i ++)
		scanf("%d", &val[i]);

	val[0] = inf;
	v[0].push_back(1);
	v[1].push_back(0);

	df(0);

	printf("%d\n", D[0] - 1);

	return 0;
}