1 # include <bits/stdc++.h>
 2 #pragma comment(linker, "/STACK:1024000000,1024000000")
 3 using namespace std;
 4 
 5 const int MAX = 100010;
 6 typedef long long int ll;
 7 struct node
 8 {
 9     int to;
10     int next;
11 }tree[MAX * 2];
12 int head[MAX], num[MAX];
13 int tol = 0;
14 int n;
15 ll sum;
16 void add(int a, int b)
17 {
18     tree[tol].to = b;
19     tree[tol].next = head[a];
20     head[a] = tol++;
21 }
22 
23 void dfs(int root, int f)
24 {
25     num[root] = 1;
26     int tep = 0;
27     for(int i = head[root]; i != -1; i = tree[i].next)
28     {
29         int son = tree[i].to;
30         if(son == f)
31             continue;
32         dfs(son, root);
33         
34         sum += (ll) tep * num[son];
35         num[root] += num[son];
36         tep += num[son];
37     }
38     sum += (ll) tep * (n - num[root]);
39 }
40 
41 int main()
42 {
43     while(scanf("%d", &n) != EOF)
44     {
45         tol = 0;
46         sum = 0;
47         memset(head, -1, sizeof(head));
48         
49         int a, b;
50         for(int i = 1; i < n; i++)
51         {
52             scanf("%d%d", &a, &b);
53             add(a, b);
54             add(b, a);
55         }
56         dfs(1, -1);
57         ll all = (ll)n * (n - 1) * (n - 2) / 6;
58         
59         printf("%I64d\n", all - sum);
60     }
61     return 0;
62 }