#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <set>
#include <map>
#include <iomanip>
#include <stack>
#include <queue>
#include <deque>
using namespace std;
typedef long long ll;
typedef pair <int, int> pii;
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
#define pb push_back
#define ppb pop_back
#define mkp make_pair
#define F first
#define S second
#define show(a) cerr << #a <<" -> "<< a <<"\n"
#define fo(a, b, c, d) for(int (a) = (b); (a) <= (c); (a) += (d))
#define foo(a, b, c ,d) for(int (a) = (b); (a) >= (c); (a) -= (d))
//#define int ll
const int N = 2e5 + 5;
const int INF = 1e9 + 5;
int n, d[N], cnt[N], mx, ans;
vector <int> g[N];
queue <int> q;
void bfs(int st) {
for(int i = 1; i <= n; ++i) {
d[i] = -1;
cnt[i] = 0;
}
d[st] = 0;
cnt[st] = 1;
q.push(st);
while(sz(q)) {
int v = q.front();
q.pop();
for(int to : g[v]) {
if(d[to] == -1) {
d[to] = d[v] + 1;
cnt[to] = cnt[v];
q.push(to);
} else if(d[to] == d[v] + 1) {
cnt[to] += cnt[v];
}
}
}
}
int main () {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n;
for(int i = 1; i <= n; ++i) {
int a, b;
cin >> a >> b;
g[a].pb(b);
g[b].pb(a);
}
for(int i = 1; i <= n; ++i) {
bfs(i);
int curmx = 0, res = 0;
for(int j = 1; j <= n; ++j) {
if(curmx < d[j]) {
curmx = d[j];
res = cnt[j];
} else if(curmx == d[j]) {
res += cnt[j];
}
}
if(mx < curmx) {
mx = curmx;
ans = res;
} else if(mx == curmx) {
ans += res;
}
}
cout << ans / 2;
return 0;
}
/*
If you only do what you can do,
You will never be more than you are now!
---------------------- -------------------------------------------- ---------------------- ----------------------
We must all suffer from one of two pains: the pain of discipline or the pain of regret.
The difference is discipline weighs grams while regret weighs tons.
*/
