#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include <vector>
#include <algorithm>

#define LOG(FMT...) fprintf(stderr, FMT)
#define eb emplace_back

using namespace std;

typedef unsigned long long ULL;
constexpr int N = 200005, TC = 4 * N, MC = N * 60;

int n, c[N];
vector<int> e[N];
int mat[N], last[N];
int bg[N], ed[N], ids;
int fa[N];

void dfs1(int x) {
	bg[x] = ++ids;
	for (int y : e[x]) {
		if (y == fa[x]) {
			continue;
		}
		fa[y] = x;
		dfs1(y);
	}
	ed[x] = ids;
}

int apr(int y, int x) {
	int l = 0, r = e[y].size(), md;
	while (l < r) {
		md = l + r >> 1;
		if (ed[e[y][md]] >= bg[x]) {
			r = md;
		} else {
			l = md + 1;
		}
	}
	return e[y][r];
}

#define L (z << 1)
#define R (z << 1 | 1)

int v[TC];
struct His {
	int z, v;
} stk[MC];
int tt;

void mdf(int ql, int qr, int c, int l = 1, int r = n, int z = 1) {
	if (l >= ql && r <= qr) {
		if (c > v[z]) {
			stk[++tt] = {z, v[z]};
			v[z] = c;
		}
	} else {
		int mid = l + r >> 1;
		if (ql <= mid) {
			mdf(ql, qr, c, l, mid, L);
		}
		if (mid < qr) {
			mdf(ql, qr, c, mid + 1, r, R);
		}
	}
}

int qry(int x, int l = 1, int r = n, int z = 1) {
	if (l == r) {
		return v[z];
	}
	int mid = l + r >> 1;
	return max(x <= mid ? qry(x, l, mid, L) : qry(x, mid + 1, r, R), v[z]);
}

int res = 1;

void dfs2(int x) {
	int y = mat[x];
	int bac = tt;
	if (y) {
		int w = qry(bg[y]);
		if (!w && y != fa[x] && x != fa[y]) {
			w = 1;
		}
		w += 2;
		if (bg[y] <= bg[x] && ed[x] <= ed[y]) {
			int z = apr(y, x);
			mdf(1, bg[z] - 1, w);
			if (ed[z] < n) {
				mdf(ed[z] + 1, n, w);
			}
		} else {
			mdf(bg[y], ed[y], w);
		}
		res = max(res, w);
	}
	for (int y : e[x]) {
		if (y != fa[x]) {
			dfs2(y);
		}
	}
	while (tt > bac) {
		auto [z, w] = stk[tt--];
		v[z] = w;
	}
}

int main() {
	scanf("%d", &n);
	for (int x = 1; x <= n; ++x) {
		scanf("%d", c + x);
		int &y = last[c[x]];
		if (y) {
			mat[x] = y;
		} else {
			y = x;
		}
	}
	for (int i = 1, x, y; i < n; ++i) {
		scanf("%d%d", &x, &y);
		e[x].eb(y), e[y].eb(x);
	}
	dfs1(1);
	dfs2(1);
	printf("%d\n", res);
	return 0;
}