#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ff first
#define ss second
int n;
vector<int> seg, v, pos;
void build(int x, int l, int r)
{
if (l + 1 == r)
{
seg[x] = v[l];
return;
}
int mid = (l + r) >> 1;
build(x << 1, l, mid), build(x << 1 | 1, mid, r);
seg[x] = max(seg[x << 1], seg[x << 1 | 1]);
}
int qry(int x, int l, int r, int ql, int qr)
{
if (ql <= l && r <= qr)
return seg[x];
int mid = (l + r) >> 1;
if (qr <= mid)
return qry(x << 1, l, mid, ql, qr);
if (ql >= mid)
return qry(x << 1 | 1, mid, r, ql, qr);
int retl = qry(x << 1, l, mid, ql, qr), retr = qry(x << 1 | 1, mid, r, ql, qr);
return max(retl, retr);
}
int ans(int x, int l, int r)
{
assert(qry(1, 0, n, l, r) == x);
if (x == 0 || l + 1 == r)
return 0;
if (pos[x] == l)
{
int rx = qry(1, 0, n, pos[x] + 1, r);
return ans(rx, pos[x] + 1, r) + pos[rx] - pos[x];
}
if (pos[x] + 1 == r)
{
int lx = qry(1, 0, n, l, pos[x]);
return ans(lx, l, pos[x]) + pos[x] - pos[lx];
}
int lx = qry(1, 0, n, l, pos[x]), rx = qry(1, 0, n, pos[x] + 1, r);
return max(ans(lx, l, pos[x]) + pos[x] - pos[lx], ans(rx, pos[x] + 1, r) + pos[rx] - pos[x]);
}
signed main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n;
v.resize(n);
for (int &i : v)
cin >> i, --i;
for (int i = 1, a, b; i < n; ++i)
cin >> a >> b;
pos.resize(n);
for (int i = 0; i < n; ++i)
pos[v[i]] = i;
seg.assign(n * 4 + 10, 0);
build(1, 0, n);
cout << ans(n - 1, 0, n) << '\n';
}
