#include<bits/stdc++.h>
using namespace std;
#define all(a) a.begin(),a.end()
#define ll long long
#define pb push_back
#define nl '\n'
#define popb pop_back()
#define sz size()
#define ld long double
#define ull unsigned long long
#define F first
#define S second
#define fix fixed<<setprecision
#define pii pair<int,int>
#define E exit (0)
#define int long long
const int inf=1e9;
int c[501][501],cnt;
vector<pii>adj[501];
map<int,bool>was;
void dfs(int u,int z,int mx,int t=0) {
was[u]=1;
if (t>mx) {
was[u]=0;
return;
}
if (u==z) {
cnt++;
was[u]=0;
return;
}
for (auto e:adj[u]) {
if (was[e.F]) {
continue;
}
dfs(e.F,z,mx,t+1);
}
was[u]=0;
return;
}
signed main() {
//freopen("planting.in","r",stdin);
//freopen("planting.out","w",stdout);
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n;
cin>>n;
for (int i=1;i<=n;i++) {
for (int j=1;j<=n;j++) {
c[i][j]=inf;
}
}
for (int i=1;i<=n;i++) {
c[i][i]=0;
int a,b;
cin>>a>>b;
c[a][b]=c[b][a]=1;
adj[a].pb({b,i});
adj[b].pb({a,i});
}
for (int k=1;k<=n;k++) {
for (int i=1;i<=n;i++) {
for (int j=1;j<=n;j++) {
c[i][j]=min(c[i][j],c[i][k]+c[k][j]);
}
}
}
int mx=0;
vector<pii>s;
for (int i=1;i<=n;i++) {
for (int j=1;j<=n;j++) {
if (mx==c[i][j]) {
s.pb({i,j});
}
if (mx<c[i][j]) {
mx=c[i][j];
s.clear();
s.pb({i,j});
}
}
}
int ans=0,i=0;
for (auto e:s) {
dfs(e.F,e.S,mx);
ans+=cnt;
for (int i=1;i<=500;i++) {
was[i]=0;
}
cnt=0;
i++;
}
cout<<ans/2;
}
