#include <bits/stdc++.h>
#define REP(v, i, j) for (int v = i; v != j; v++)
#define FORI(v) for (auto i : v)
#define FORJ(v) for (auto j : v)
#define OUT(v, a) \
    FORI(v)       \
    cout << i << a;
#define OUTS(v, a, b)      \
    cout << v.size() << a; \
    OUT(v, b)
#define in(a, n) \
    REP(i, 0, n) \
    cin >> a[i];
#define SORT(v) sort(begin(v), end(v))
#define REV(v) reverse(begin(v), end(v))
#define MEMSET(m) memset(m, -1, sizeof m)
#define pb push_back
#define fi first
#define se second
#define detachIO                      \
    ios_base::sync_with_stdio(false); \
    cin.tie(0);                       \
    cout.tie(0);
    
using namespace std;
template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
bool operator==(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y) {
    if(__x.size() != __y.size()) return false;
    return std::equal(__x.begin(), __x.end(), __y.begin());
}
typedef pair<int, int> pii;
typedef pair<pii, int> piii;
typedef pair<pii, pii> piiii;
const int MOD = 1e9+7;
struct modint {
    long long val;
    modint() = default;
    modint(int _val): val(_val){}
    modint operator+(modint b){ return ((this->val + b.val)%MOD); }
    modint operator-(modint b){ return ((MOD + this->val - b.val)%MOD); }
    modint operator*(modint b){ return ((this->val * b.val)%MOD); }
    modint operator^(int a){
        if(a==0)return 1;
        if(a==1)return *this;
        return (((*this)*(*this))^(a>>1))*((*this)^(a&1)); 
    }
};
modint invert(modint a){
    return a^(MOD-2);
}
modint operator/(modint a, modint b){
    return a*invert(b);
}
vector<int> add[200100];
vector<int> adj[200100];
int p[200100];
int m[200100];
int dfs(int node, int parent){
    int ans=m[node];
    FORI(adj[node]){
        if(i!=parent)ans=max(ans,dfs(i,node)+1);
    }
    return ans;
}
int main(){
    detachIO;
    int n;cin>>n;
    REP(i,1,n+1){
        cin>>p[i];
    }
    REP(i,1,n){
        int a,b;cin>>a>>b;
        a=p[a];
        b=p[b];
        if(a<b)swap(a,b);
        add[a].pb(b);
    }
    REP(i,1,n+1){
        adj[i]=add[i];
        FORJ(adj[i])adj[j].pb(i);
        m[i]=dfs(i,-1);
    }
    cout<<m[n];
}
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