// Problem URL: https://oj.uz/problem/view/JOI23_ho_t4
// Start Time: 5/27/2025, 9:44:51 PM
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define mp make_pair
#define pb push_back
#define F first
#define S second
#define debug(x) std::cout << #x << ": " << x << "\n"
#define all(v) v.begin(), v.end()
#define li(i,a,b) for (int i = a; i < b; i++)
#define endl '\n'
#define mem(name,val) memset(name,val,sizeof(name))
#define max(a,b) max<ll>(a,b)
#define min(a,b) min<ll>(a,b)
const int nmax = 2e5+3;
vector<int> adj[nmax];
int p[nmax], pos[nmax];
int n;
int t[2*nmax]; // promeni u sparse table jer nema update
void build(){for(int x = n-1; x>0; x--)t[x]=max(t[2*x],t[2*x+1]);}
int get (int l, int r){
int res = -1;
for(l+=n,r+=n;l<r;l>>=1,r>>=1){
if(l&1)res=max(res,t[l++]);
if(r&1)res=max(res,t[--r]);
}
return res;
}
set<int> obst;
ll maxmoves(int mn){
if(obst.count(mn-1) && obst.count(mn+1))return 0; // base case
auto it = obst.upper_bound(mn);
int rb = *it;
it--;
int lb = *it;
int hl = get(lb+1-1, mn-1);
int l = (hl == -1 ? mn : pos[hl]);
int hr = get(mn+1-1, rb-1);
int r = (hr == -1 ? mn : pos[hr]);
ll left = 0, right = 0;
obst.insert(mn);
if(l!=mn)
left = abs<ll>(mn-l) + maxmoves(l);
if(r!=mn)
right = abs<ll>(r-mn)+ maxmoves(r);
return max(left,right);
}
int main()
{
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
cin>>n;
li(i,1,n+1){
cin>>p[i];
t[i+n-1] = p[i];
pos[p[i]]=i;
}
build();
li(i,0,n-1){
int a,b;
cin>>a>>b;
adj[a].pb(b);
adj[b].pb(a);
}
obst.insert(0);
obst.insert(n+1);
cout<<maxmoves(pos[n]);
return 0;
}
