#include <bits/stdc++.h>
using namespace std;
#define task "main"
#define no "NO"
#define yes "YES"
#define F first
#define S second
#define vec vector
#define _mp make_pair
#define ii pair<int, int>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define evoid(val) return void(std::cout << val)
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)
const int MAX_N = (int)1e5 + 5;
int numNode;
int a[MAX_N];
vector<ii> adj[MAX_N];
namespace sub1 {
bool valid() {
return numNode <= 5000;
}
int ans = 0;
void dfs(int u, int p, long long sum) {
sum += a[u];
for (ii e : adj[u]) {
int v = e.F, w = e.S;
if (v == p) continue;
if (sum < w) continue;
ans++;
dfs(v, u, sum - w);
}
}
void solve() {
FOR(u, 1, numNode) dfs(u, -1, 0);
cout << ans << "\n";
}
}
namespace sub2 {
bool valid() {
FOR(i, 1, numNode) if ((int)adj[i].size() > 2) return false;
return true;
}
long long ans = 0;
int d[MAX_N];
void solve() {
FOR(i, 1, numNode - 1) {
for (ii e : adj[i]) if (e.F != i - 1) d[i + 1] = e.S;
}
int l = 1;
long long sum = a[1];
FOR(i, 2, numNode) {
if (sum < d[i]) sum = 0, l = i;
else {
sum -= d[i];
ans += (i - l);
}
sum += a[i];
}
cout << ans << "\n";
}
}
void solve() {
cin >> numNode;
FOR(i, 1, numNode) cin >> a[i];
FOR(i, 1, numNode - 1) {
int u, v, w;
cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
}
if (sub1::valid()) sub1::solve();
}
int32_t main() {
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
bool multitest = 0;
int numTest = 1;
if (multitest) cin >> numTest;
while (numTest--) {
solve();
}
return 0;
}
/* Lak lu theo dieu nhac!!!! */
