# include <cstdio>
# include <set>
# include <stack>
# include <vector>
using namespace std;

# define y second
# define verf ++poz == hg ? fread ( ch, 1, hg, stdin ), poz = 0 : 0

const char *FIN = "guvern.in", *FOU = "guvern.out";
const int MAX = 100005, oo = 0x3f3f3f3f, hg = 1 << 13;

bool viz[MAX];
int N, poz, dp[MAX], grad[MAX];
vector <int> G[MAX], T[MAX][2];
stack < int, vector <int> > son[MAX];
set < pair <int, int> > S;
char ch[hg];

inline void cit ( int &x ) {
    if ( ch[0] == '\0' ) fread ( ch, 1, hg, stdin ) ;
    else for ( ; ch[poz] < '0' || ch[poz] > '9' ; verf ) ;
    for ( x = 0 ; ch[poz] >= '0' && ch[poz] <= '9' ; x = x * 10 + ch[poz] - '0', verf ) ;
}

int search (int nod, int c) {
    int sol = 0;
    for (vector <int> :: iterator it = T[nod][c].begin (); it != T[nod][c].end (); ++it)
        sol += search (*it, 0);
    return max (dp[nod], sol);
}

void dfs (int nod) {
    viz[nod] = 1;
    set < pair <int, int> > :: iterator it = S.upper_bound (make_pair (grad[nod], 0));
    if (son[it -> y].empty ())
        T[it -> y][1].push_back (nod);
    else T[son[it -> y].top ()][0].push_back (nod);
    son[it -> y].push (nod), S.insert (make_pair (grad[nod], nod));
    for (vector <int> :: iterator i = G[nod].begin (); i != G[nod].end (); ++i) {
        if (viz[*i]) continue;
        dfs (*i);
    }
    S.erase (make_pair (grad[nod], nod)), son[it -> y].pop ();
    dp[nod] = search (nod, 1) + 1;
}

void init (void) {
    grad[0] = oo, G[0].push_back (1), G[1].push_back (0);
}

int main (void) {
    freopen (FIN, "r", stdin);

    cit (N);
    for (int i = 1, x, y; i < N; ++i) {
        cit (x), cit (y);
        G[x].push_back (y);
        G[y].push_back (x);
    }
    for (int i = 1; i <= N; ++i)
        cit (grad[i]);
    init (), dfs (0);
    fprintf (fopen (FOU, "w"), "%d", --dp[0]);
}