#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define re exit(0);
const int maxn = 100009;
int n,arr[maxn];
vector <pair <int,int>> adj[maxn];
ll res;
int sz[maxn];
bool del[maxn];
int countChild(int node,int par) {
sz[node] = 1;
for (pair <int,int> x : adj[node]) if (x.first != par && !del[x.first]) {
sz[node] += countChild(x.first,node);
}
return sz[node];
}
int findCentroid(int node,int par,int n) {
for (pair <int,int> x : adj[node]) if (x.first != par && !del[x.first] && sz[x.first] > n / 2) {
return findCentroid(x.first,node,n);
}
return node;
}
//0:up,1:down
vector <pair <ll,bool>> cont[maxn];
bool cmp(pair <ll,bool> a,pair <ll,bool> b) {
if (a.first != b.first) return a.first > b.first;
return a.second < b.second;
}
void dfs_down(int node,int par,vector <pair <ll,bool>> & cont,ll curr,ll need) {
cont.push_back({need,1});
curr += arr[node];
for (pair <int,int> x : adj[node]) if (x.first != par && !del[x.first]) {
dfs_down(x.first,node,cont,max(0ll,curr - x.second),need + max(0ll,x.second - curr));
}
}
void dfs_up(int node,int par,vector <pair <ll,bool>> & cont,ll minval,ll sum) {
if (minval >= 0) cont.push_back({sum,0});
for (pair <int,int> x : adj[node]) if (x.first != par && !del[x.first]) {
dfs_up(x.first,node,cont,min(0ll,minval) + arr[x.first] - x.second,sum + arr[x.first] - x.second);
}
}
void addres(int node) {
vector <pair <ll,bool>> total;
for (pair <int,int> x : adj[node]) if (!del[x.first]) {
int child = x.first,w = x.second;
cont[child].clear();
dfs_down(child,node,cont[child],0,w);
dfs_up(child,node,cont[child],arr[child] - w,arr[node] + arr[child] - w);
for (pair <ll,bool> x : cont[child]) total.push_back(x);
sort(cont[child].begin(),cont[child].end(),cmp);
}
total.push_back({arr[node],0});
total.push_back({0,1});
sort(total.begin(),total.end(),cmp);
// for (pair <ll,bool> x : total) cout << x.first << " " << x.second << '\n';
int cntup = 0;
for (pair <ll,bool> x : total) {
if (x.second == 0) cntup++;
else res += cntup;
}
//tru cac thang xuat phat va ket thuc tai cung cay con
res--;
for (pair <int,int> x : adj[node]) if (!del[x.first]) {
cntup = 0;
for (pair <ll,bool> a : cont[x.first]) {
if (a.second == 0) cntup++;
else res -= cntup;
}
}
}
void solve(int node) {
int cnt = countChild(node,0);
int ct = findCentroid(node,0,cnt);
addres(ct);
del[ct] = 1;
for (pair <int,int> x : adj[ct]) if (!del[x.first]) solve(x.first);
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(nullptr);
// freopen(".inp","r",stdin);
// freopen(".out","w",stdout);
cin >> n;
for (int i = 1;i <= n;i++) cin >> arr[i];
for (int i = 1;i < n;i++) {
int u,v,w;cin >> u >> v >> w;
adj[u].push_back({v,w});
adj[v].push_back({u,w});
}
solve(1);
// addres(2);
cout << res;
}
