#include <bits/stdc++.h>using namespace std;#define rep(i, a, b)	for (int i(a); i <= (b); ++i)#define dec(i, a, b)	for (int i(a); i >= (b); --i)typedef long long LL;const int N = 200010;int root[N];int ls[N * 40], rs[N * 40], lis[N * 40], lds[N * 40];int ncnt, n, ans;int ret = 0;vector <int> v[N];int val[N];int sx[N];int icnt = 0;void merge(int &x, int y){	if (!x || !y){		x = x + y;		return;	}	lis[x] = max(lis[x], lis[y]);	lds[x] = max(lds[x], lds[y]);	ret = max(ret, max(lis[ls[x]] + lds[rs[y]], lds[rs[x]] + lis[ls[y]]));	merge(ls[x], ls[y]);	merge(rs[x], rs[y]);}void modify(int &x, int l, int r, int t, int v, int *a){	if (!x) x = ++ncnt;	a[x] = max(a[x], v);	if (l == r) return;	int mid = (l + r) >> 1;	if (t <= mid) modify(ls[x], l, mid, t, v, a);	else modify(rs[x], mid + 1, r, t, v, a);}int query(int x, int l, int r, int ql, int qr, int *a){	if (l > r) return 0;	if (!x) return 0;	if (ql <= l && r <= qr) return a[x];	int ret = 0, mid = (l + r) >> 1;	if (ql <= mid) ret = max(ret, query(ls[x], l, mid, ql, qr, a));	if (qr >  mid) ret = max(ret, query(rs[x], mid + 1, r, ql, qr, a));	return ret;}void dfs(int x, int fa){	for (auto u : v[x]){		if (u == fa) continue;		dfs(u, x);	}	ret = 0;	int nlis = 0, nlds = 0, ilis, ilds;	for (auto u : v[x]){		if (u == fa) continue;		ilis = query(root[u], 1, icnt, 1, val[x] - 1, lis);		ilds = query(root[u], 1, icnt, val[x] + 1, icnt, lds);		merge(root[x], root[u]);		ans = max(ans, ilis + nlds + 1);		ans = max(ans, ilds + nlis + 1);		nlis = max(nlis, ilis);		nlds = max(nlds, ilds);	}	ans = max(ans, ret);	modify(root[x], 1, icnt, val[x], nlis + 1, lis);	modify(root[x], 1, icnt, val[x], nlds + 1, lds);}int main(){	scanf("%d", &n);	rep(i, 1, n){		scanf("%d", val + i);		sx[++icnt] = val[i];	}	sort(sx + 1, sx + icnt + 1);	icnt = unique(sx + 1, sx + icnt + 1) - sx - 1;	rep(i, 1, n) val[i] = lower_bound(sx + 1, sx + icnt + 1, val[i]) - sx;	rep(i, 2, n){		int x, y;		scanf("%d%d", &x, &y);		v[x].push_back(y);		v[y].push_back(x);	}	dfs(1, 0);	printf("%d\n", ans);	return 0;}