#include <bits/stdc++.h>

using namespace std;
const int N = 2005; 
int n, w[N], d[N], f1[N], f2[N], ans, mk[N], op; 
vector <int> e[N];

void dfs (int p, int fa) {
    d[p] = d[fa]+1; 
    for (auto i : e[p]) {
        if (i == fa) continue; 
        dfs(i, p); 
    }
}

void dfs2 (int p) {
    mk[p] = 1; int k1, k2;
    if (w[p] > f1[d[p]-1] && w[p] < f2[d[p]+1]) {
        k1 = f1[d[p]]; k2 = f2[d[p]]; 
//        cout << p << " "; 
        f1[d[p]] = max(f1[d[p]], w[p]); ++ans; 
        f2[d[p]] = min(f2[d[p]], w[p]);
    }
    else return;
    for (auto i : e[p]) {
        if (mk[i]) continue; 
        dfs2(i); 
    }
    f1[d[p]] = k1; f2[d[p]] = k2;
}

int main () {
    freopen("touch.in", "r", stdin); 
    freopen("touch.out", "w", stdout); 
    cin >> n;
    for (int i = 1;i <= n;i++) cin >> w[i]; 
    for (int i = 1;i < n;i++) {
        int x, y; cin >> x >> y;
        e[x].push_back(y); e[y].push_back(x); 
    } 
    dfs(1, 0); 
    memset(f2, 0x3f, sizeof(f2)); 
    for (op = 1;op <= n;op++) {
        memset(mk, 0, sizeof(mk)); 
//        cout << op << endl;
        
        dfs2(op); 
//        cout << endl;
    }
    ans -= n; ans /= 2;
    cout << ans;
    return 0;
}