#include <bits/stdc++.h>
#define int long long
using namespace std;
typedef array<int, 2> pr;
const int MAX = 100001;
vector<pr> adj[MAX];
vector<int> comp;
int sz[MAX], A[MAX], ans, tree[MAX * 8], S;
bool chk[MAX];
int get_sz(int node, int par) {
sz[node] = 1;
for (pr i : adj[node]) {
if (i[0] == par || chk[i[0]])
continue;
sz[node] += get_sz(i[0], node);
}
return sz[node];
}
int get_cent(int node, int par, int cap) {
for (pr i : adj[node]) {
if (i[0] == par || chk[i[0]])
continue;
if (sz[i[0]] * 2 > cap)
return get_cent(i[0], node, cap);
}
return node;
}
int query(int n, int s, int e, int l, int r) {
if (r < s || e < l)
return 0;
else if (l <= s && e <= r)
return tree[n];
else {
int m = s + e >> 1;
return query(n << 1, s, m, l, r) + query(n << 1 | 1, m + 1, e, l, r);
}
}
void update(int n, int s, int e, int idx, int v) {
if (idx < s || e < idx)
return;
else if (s == e)
tree[n] += v;
else {
int m = s + e >> 1;
update(n << 1, s, m, idx, v), update(n << 1 | 1, m + 1, e, idx, v);
tree[n] = tree[n << 1] + tree[n << 1 | 1];
}
}
int query(int n) {
n = lower_bound(comp.begin(), comp.end(), n) - comp.begin() + 1;
return query(1, 1, S, 1, n);
}
void update(int n, int v) {
n = lower_bound(comp.begin(), comp.end(), n) - comp.begin() + 1;
update(1, 1, S, n, v);
}
void dfs0(int node, int par, int val, int mn) {
comp.push_back(-val);
if (A[node] + mn >= 0)
comp.push_back(A[node] + mn);
for (pr i : adj[node]) {
if (i[0] == par || chk[i[0]])
continue;
dfs0(i[0], node, min(val, val + A[node] - i[1]), min(0ll, mn + A[node]) - i[1]);
}
}
void dfs1(int node, int par, int val) {
update(-val, 1);
for (pr i : adj[node]) {
if (i[0] == par || chk[i[0]])
continue;
dfs1(i[0], node, min(val, val + A[node] - i[1]));
}
}
void dfs2(int node, int par, int mn) {
if (A[node] + mn >= 0)
ans += query(A[node] + mn);
for (pr i : adj[node]) {
if (i[0] == par || chk[i[0]])
continue;
dfs2(i[0], node, min(0ll, mn + A[node]) - i[1]);
}
}
void dfs3(int node, int par, int val) {
update(-val, -1);
for (pr i : adj[node]) {
if (i[0] == par || chk[i[0]])
continue;
dfs3(i[0], node, min(val, val + A[node] - i[1]));
}
}
void dnc(int node) {
int cent = get_cent(node, -1, get_sz(node, -1));
chk[cent] = true, comp.clear();
comp.push_back(0);
for (pr i : adj[cent]) {
if (chk[i[0]])
continue;
dfs0(i[0], cent, A[cent] - i[1], -i[1]);
}
sort(comp.begin(), comp.end()), comp.erase(unique(comp.begin(), comp.end()), comp.end()), S = comp.size();
update(0, 1);
for (pr i : adj[cent]) {
if (chk[i[0]])
continue;
dfs1(i[0], cent, A[cent] - i[1]);
}
ans += query(0);
for (pr i : adj[cent]) {
if (chk[i[0]])
continue;
dfs3(i[0], cent, A[cent] - i[1]);
dfs2(i[0], cent, -i[1]);
dfs1(i[0], cent, A[cent] - i[1]);
}
update(0, -1);
for (pr i : adj[cent]) {
if (chk[i[0]])
continue;
dfs3(i[0], cent, A[cent] - i[1]);
}
for (pr i : adj[cent]) {
if (chk[i[0]])
continue;
dnc(i[0]);
}
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
int N, X, Y, Z;
cin >> N;
for (int i = 1; i <= N; i++)
cin >> A[i];
for (int i = 1; i < N; i++) {
cin >> X >> Y >> Z;
adj[X].push_back({Y, Z}), adj[Y].push_back({X, Z});
}
dnc(1);
ans -= N;
cout << ans << '\n';
return 0;
}
