#include<bits/stdc++.h>
        
using namespace std;

int n, ans = 0;

struct node
{
    int dep;
    int fa;
    int w;
    vector<int> son;
};

vector<node> v(2005);
int f[2005][20];

inline void buildtree(int step, int fa, int cnt)
{
    v[step].dep = cnt;
    v[step].fa = fa;
    int del = -1;
    for (int i = 0; i < v[step].son.size(); ++i)
    {
        if(v[step].son[i] == fa)
            del = i;
        else
            buildtree(v[step].son[i],step,cnt+1);
    }
    if(del != -1)
        v[step].son.erase(v[step].son.begin()+del);
}

inline void dfs(int u, int fa)
{
    int num = v[u].son.size();
    v[u].dep = v[fa].dep+1;
    for (int i = 0; i <= log2(n); ++i)
        f[u][i+1] = f[f[u][i]][i];
    for (int i = 0; i < num; ++i)
    {
        int cd = v[u].son[i];
        f[cd][0] = u;
        dfs(cd,u);
    }
}

inline int LCA(int x, int y)
{
    if(v[x].dep < v[y].dep)
        swap(x,y);
    for (int i = log2(n); i >= 0; --i)
    {
        if(f[x][i] > 0 && v[f[x][i]].dep >= v[y].dep)
            x = f[x][i];
        if(x == y)
            return x;
            
    }
    for (int i = log2(n); i >= 0; --i)
    {
        if(f[x][i] != f[y][i])
        {
            x = f[x][i];
            y = f[y][i];
        }
    }
    return f[x][0];
}

inline bool Ishigh(int x, int y, int z)
{
    vector<int> l;
    deque<int> q;
    q.push_back(x);
    l.push_back(x);
    l.push_back(y);
    while(q.front() != z)
    {
        int a = q.front();
        q.pop_front();
        q.push_back(v[a].fa);
        l.push_back(q.front());
    }
    q.clear();
    q.push_back(y);
    while(q.front() != z)
    {
        int a = q.front();
        q.pop_front();
        q.push_back(v[a].fa);
        l.push_back(q.front());
    }
    q.clear();
    for (int i = 0; i < l.size(); ++i)
        for (int j = i+1; j < l.size(); ++j)
        {
            int a = i, b = j;
            if(v[l[a]].dep < v[l[b]].dep)
                swap(a,b);
            if(v[l[a]].dep > v[l[b]].dep && v[l[a]].w <= v[l[b]].w)
                return false;
        }
    return true;
}
   
int main()
{
    freopen("touch.in", "r", stdin);
   	freopen("touch.out", "w", stdout);
           	
    ios::sync_with_stdio(false);
   	cin.tie(0); cout.tie(0);
        	
    cin >> n;
    
    for (int i = 1; i <= n; ++i)
        cin >> v[i].w;
    for (int i = 1; i < n; ++i)
    {
        int x, y;
        cin >> x >> y;
        v[x].son.push_back(y);
        v[y].son.push_back(x);
    }
    
    buildtree(1,0,1);
    
    dfs(1,0);
    //cout << '\n';
    for (int i = 1; i <= n; ++i)
        for (int j = i+1; j <= n; ++j)
        {
            int id = LCA(i,j);
            if(Ishigh(i,j,id) == true)
            {
                ans++;
                //cout << i << " " << j << " " << id << '\n';
            }        
        }
    
    cout << ans;
        	
   	return 0;
}