// Author: kyEEcccccc

#include <bits/stdc++.h>

using namespace std;

using LL = long long;
using ULL = unsigned long long;

#define F(i, l, r) for (int i = (l); i <= (r); ++i)
#define FF(i, r, l) for (int i = (r); i >= (l); --i)
#define MAX(a, b) ((a) = max(a, b))
#define MIN(a, b) ((a) = min(a, b))
#define SZ(a) ((int)((a).size()) - 1)

constexpr int N = 505, K = 9;

int n;
int tar[N];
vector<int> chi[N];
int par[N], dep[N];
int dfn[N], idfn[N], cur_dfn;
array<int, 2> lca_mn[505][N];

void init_tree(int u)
{
	dfn[u] = ++cur_dfn;
	idfn[dfn[u]] = u;
	for (auto v : chi[u])
	{
		par[v] = u;
		chi[v].erase(find(chi[v].begin(), chi[v].end(), u));
		dep[v] = dep[u] + 1;
		init_tree(v);
	}
}

int get_lca(int u, int v)
{
	if (u == v) return u;
	u = dfn[u], v = dfn[v];
	if (u > v) swap(u, v);
	int k = __lg(v - u);
	return par[min(lca_mn[k][u + 1], lca_mn[k][v - (1 << k) + 1])[1]];
}

int get_dis(int u, int v)
{
	int lca = get_lca(u, v);
	return dep[u] + dep[v] - dep[lca] * 2;
}

bool tg[N], vv[N];

struct Cir
{
	vector<int> pts;
	int rt;
};

vector<Cir> cs;
int dd[N][N];
vector<array<int, 3>> ed;

struct Dsu
{
	int ff[N], sz[N];

	void init(int nn)
	{
		iota(ff + 1, ff + nn + 1, 1);
		fill(sz + 1, sz + nn + 1, 1);
	}

	int get_anc(int u) { return u == ff[u] ? u : (ff[u] = get_anc(ff[u])); }

	bool merge(int u, int v)
	{
		u = get_anc(u), v = get_anc(v);
		if (u == v) return false;
		if (sz[u] > sz[v]) swap(u, v);
		sz[v] += sz[u];
		ff[u] = v;
		return true;
	}
} dsu;

signed main(void)
{
	// freopen(".in", "r", stdin);
	// freopen(".out", "w", stdout);
	ios::sync_with_stdio(0), cin.tie(nullptr);

	cin >> n;
	F(i, 1, n) cin >> tar[i];
	F(i, 1, n - 1)
	{
		int u, v;
		cin >> u >> v;
		chi[u].push_back(v);
		chi[v].push_back(u);
	}

	par[1] = 0;
	dep[1] = 1;
	init_tree(1);
	F(i, 1, n) lca_mn[0][dfn[i]] = {dep[i], i};
	F(k, 1, K - 1) F(i, 1, n - (1 << k) + 1)
		lca_mn[k][i] = min(lca_mn[k - 1][i], lca_mn[k - 1][i + (1 << (k - 1))]);

	cs.push_back({{1}, 1});
	int ans = 0;
	F(i, 1, n)
	{
		if (vv[i] || tar[i] == i) continue;
		int p = i;
		F(j, 1, n) tg[j] = false;
		while (!vv[p])
		{
			int u = p, v = tar[p], lca = get_lca(u, v);
			ans += get_dis(u, v);
			while (u != lca)
			{
				tg[u] = true;
				u = par[u];
			}
			while (v != lca)
			{
				tg[v] = true;
				v = par[v];
			}
			tg[lca] = true;
			vv[p] = true;
			p = tar[p];
		}
		cs.push_back({{}, 0});
		F(j, 1, n)
		{
			if (!tg[j]) continue;
			cs.back().pts.push_back(j);
			if (cs.back().rt == 0 || dep[cs.back().rt] > dep[j]) cs.back().rt = j;
		}
	}

	memset(dd, 0x3f, sizeof (dd));
	F(i, 1, SZ(cs))
	{
		F(j, 1, n) tg[j] = false;
		for (auto x : cs[i].pts) 
		{
			tg[x] = true;
		}
		F(j, 0, i - 1)
		{
			dd[i][j] = INT_MAX / 2;
			for (auto x : cs[j].pts)
			{
				if (tg[x]) { dd[i][j] = 0; break; }
				MIN(dd[i][j], get_dis(x, cs[i].rt));
			}
			if (dd[i][j] == 0) continue;
			for (auto x : cs[i].pts)
			{
				MIN(dd[i][j], get_dis(cs[j].rt, x));
			}
			ed.push_back({dd[i][j], i + 1, j + 1});
		}
	}
	sort(ed.begin(), ed.end());
	dsu.init(cs.size());
	for (auto ee : ed)
	{
		if (dsu.merge(ee[1], ee[2]))
		{
			ans += ee[0] * 2;
		}
	}

	cout << ans << endl;
	
	return 0;
}