#include <fstream>
#include <vector>
#include <bitset>
using namespace std;

ifstream f("guvern.in");
ofstream g("guvern.out");

vector<int> G[200001];
int n;
long long nd[200001];

int dp[200001];
bitset<200001> viz;
auto mx = [](int a, int b) {return (a > b ? a : b); };
void dyn(long long x, long long v)
{
	for (auto it : G[x])
	{
		if (!viz[it])
		{
			if (nd[it] < nd[x])
			{
				viz[it] = 1;
				if (G[it].size() == 1) dp[it] = 1;
				if (dp[it] == 0) dyn(it, nd[it]);
				if (dp[x] == 0 || dp[it] + 1 > dp[x])
					dp[x] = dp[it] + 1;
			}
			else if (dp[it] == 0) dyn(it, v);
		}
	}
}

int main()
{
	f >> n;
	int x, y;
	for (int i = 1; i < n; i++)
	{
		f >> x >> y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
	for (int i = 1; i <= n; i++)
		f >> nd[i];
	for (int i = 1; i <= n; i++)
	{
		if (!viz[i])
			dyn(i, nd[i]);
	}
	int m = 0;
	for (int i = 1; i <= n; i++)
		if (dp[i] > m) m = dp[i];
	g << m + 1;
	return 0;
}