#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define MP make_pair
#define PB push_back
#define ft first
#define sd second
#define sz(x) ((int)x.size())
#define pil pair<int,ll>
#define pli pair<ll,ll>
using namespace std;
using namespace __gnu_pbds;
template <class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
const int N = 100100;
const int oo = 2e9;
ordered_set<pli> st;
vector<pil> g[N];
ll ans = 0, a[N];
int n, siz[N];
bool mrk[N];
void build_sz(int v, int p){
siz[v] = 1;
for (pil u : g[v]){
if (u.ft == p || mrk[u.ft]) continue;
build_sz(u.ft, v);
siz[v] += siz[u.ft];
}
}
int search(int v, int p, int SZ){
for (pil u : g[v])
if (u.ft != p && !mrk[u.ft] && siz[u.ft] > SZ / 2)
return search(u.ft, v, SZ);
return v;
}
void check_up(int v, int p, ll sm, int p_ed, ll sf){
sf = min(sf - p_ed + a[v], 0ll);
sm += a[v] - p_ed;
if (sf == 0)
ans += st.order_of_key(MP(sm, oo));
for (pil u : g[v]) {
if (u.ft == p || mrk[u.ft]) continue;
check_up(u.ft, v, sm, u.sd, sf);
}
}
void insrt(int v, int p, int p_ed, ll sm, ll mn, ll sta){
mn = min(mn, sm - p_ed);
st.insert(MP(-mn, v));
sm += a[v] - p_ed;
if (-mn <= sta)
ans++;
for (pil u : g[v]){
if (u.ft == p || mrk[u.ft]) continue;
insrt(u.ft, v, u.sd, sm, mn, sta);
}
}
void build_cd(int v){
build_sz(v, -1);
v = search(v, -1, siz[v]);
st.clear();
st.insert(MP(0, v));
for (int it = 0; it < sz(g[v]); it++){
pil u = g[v][it];
if (mrk[u.ft]) continue;
check_up(u.ft, v, a[v], u.sd, 0);
insrt(u.ft, v, u.sd, 0, 0, a[v]);
}
st.clear();
for (int it = sz(g[v]) - 1; it >= 0; it--){
pil u = g[v][it];
if (mrk[u.ft]) continue;
check_up(u.ft, v, a[v], u.sd, 0);
insrt(u.ft, v, u.sd, 0, 0, -1);
}
mrk[v] = 1;
for (pil u : g[v])
if (!mrk[u.ft])
build_cd(u.ft);
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef _LOCAL
freopen("in.txt","r",stdin);
#endif // _LOCAL
cin >> n;
for (int i = 0; i < n; i++)
cin >> a[i];
for (int i = 1; i < n; i++){
int x, y, w; cin >> x >> y >> w;
x--; y--;
g[x].PB(MP(y, w));
g[y].PB(MP(x, w));
}
build_cd(0);
cout << ans;
return 0;
}
