1 #include<cstdio>
 2 #include<algorithm>
 3 #include<cstring>
 4 #include<iostream>
 5 #include<cmath>
 6 #include<cctype>
 7 #include<set>
 8 #include<queue>
 9 #include<vector>
10 #include<map>
11 using namespace std;
12 typedef long long LL;
13
14 inline int read() {
15     int x=0,f=1;char ch=getchar();for(;!isdigit(ch);ch=getchar())if(ch=='-')f=-1;
16     for(;isdigit(ch);ch=getchar())x=x*10+ch-'0';return x*f;
17 }
18
19 const int N = 300005;
20
21 struct Edge{
22     int to, nxt, w;
23     Edge() {}
24     Edge(int a,int b,int c) { to = a, nxt = b, w = c; }
25 }e[N << 1];
26 int head[N], w[N], En;
27
28 inline void add_edge(int u,int v,int w) {
29     ++En; e[En] = Edge(v, head[u], w); head[u] = En;
30     ++En; e[En] = Edge(u, head[v], w); head[v] = En;
31 }
32
33 LL f[N], Ans;
34 void dfs(int u,int fa) {
35     f[u] = w[u];
36     LL mx1 = -1e18, mx2 = -1e18;
37     for (int i = head[u]; i; i = e[i].nxt) {
38         int v = e[i].to;
39         if (v == fa) continue;
40         dfs(v, u);
41         LL t = f[v] - e[i].w;
42         if (t > mx1) mx2 = mx1, mx1 = t;
43         else if (t > mx2) mx2 = t;
44         if (f[v] > e[i].w) f[u] = max(f[u], f[v] - e[i].w + w[u]);
45     }
46     Ans = max(Ans, f[u]);
47     Ans = max(Ans, mx1 + mx2 + w[u]);
48 }
49
50 int main() {
51     int n = read();
52     for (int i = 1; i <= n; ++i) w[i] = read();
53     for (int i = 1; i < n; ++i) {
54         int u = read(), v = read(), w = read();
55         add_edge(u, v, w);
56     }
57     dfs(1, 0);
58     cout << Ans;
59     return 0;
60 }