#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <cmath>
#include <iostream>
#include <algorithm>
#include <random>
#include <functional>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
using namespace std;

#define lowbit(x) ((x) & -(x))
#define lson l,mid,id<<1
#define rson mid+1,r,id<<1|1
#define ls id<<1
#define rs id<<1|1
#define MID(l,r) ((l)+(((r)-(l))>>1))
#define fi first
#define se second
#define mk make_pair
#define mt make_tuple
#define pb push_back
#define epb emplace_back
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()

using LL = long long;
//using LL = __int64;
using pii = pair<int, int>;
using pdd = pair<double, double>;
using pLL = pair<LL, LL>;

const int INF = 0x3f3f3f3f;
const LL LINF = 0x3f3f3f3f3f3f3f3f;
const double pi = acos(-1.0);
const double eps = 1e-8;
const int e5 = 100000; // 1e5
const int e6 = 1000000; //1e6;
const int MOD = 1000000007; //1e9 + 7
//const int MOD = 998244353;
//const int MOD = 911451407;

template< typename T = int > inline T read()
{
    char c = '\0';
    bool f = false;
    T x = 0;
    while(c < '0' || '9' < c) {if(c == '-') f = true; c = getchar();}
    while('0' <= c && c <= '9') {x = (x << 1) + (x << 3) + (c & 0xf); c = getchar();}
    if(f) return -x;
    return x;
}
template< typename T > inline void read(T &x) {x = read<T>();}
template < typename T, typename ...Args > inline void read(T &x, Args &...args) {read(x); read(args...);}

template < typename T > inline void getmin(T &x, T y) {if(y < x) x = y;}
template < typename T > inline void getmax(T &x, T y) {if(x < y) x = y;}
template < typename X, typename Y > inline void depair(X &x, Y &y, const pair<X, Y> &pr) {x = pr.fi; y = pr.se;}

inline int sig(double x) {return x < -eps ? -1 : eps < x;}
LL fp(LL a, LL n, LL mod = MOD)
{
    if(n < 0) a = fp(a, mod - 2, mod), n = -n;
    LL res = 1;
    for(; n; n >>= 1, a = a * a % mod)
        if(n & 1)
            res = res * a % mod;
    return res;
}

struct Mint
{
    int x;
    Mint():x(0) {}
    Mint(int _x): x(_x)
    {
        if(x < 0 || x >= MOD) x %= MOD;
        if(x < 0) x += MOD;
    }
    Mint(LL _x)
    {
        if(_x < 0 || _x >= MOD) _x %= MOD;
        if(_x < 0) _x += MOD;
        x = _x;
    }
    Mint operator - () const {return Mint(MOD - x);}
    Mint operator + (const Mint &rhs) const {return Mint(x + rhs.x >= MOD ? x + rhs.x - MOD : x + rhs.x);}
    Mint operator - (const Mint &rhs) const {return Mint(x - rhs.x < 0 ? x - rhs.x + MOD : x - rhs.x);}
    Mint operator * (const Mint &rhs) const {return Mint((LL)x * rhs.x % MOD);}
    Mint operator / (const Mint &rhs) const {return Mint((LL)x * fp(rhs.x, -1) % MOD);}
    bool operator == (const Mint &rhs) const {return x == rhs.x;}
    bool operator != (const Mint &rhs) const {return x != rhs.x;}
    Mint& operator += (const Mint &rhs) {x += rhs.x; if(x >= MOD) x -= MOD; return *this;}
    Mint& operator -= (const Mint &rhs) {x -= rhs.x; if(x < 0) x += MOD; return *this;}
    Mint& operator *= (const Mint &rhs) {x = (LL)x * rhs.x % MOD; return *this;}
    Mint& operator /= (const Mint &rhs) {x = (LL)x * fp(rhs.x, -1) % MOD; return *this;}
    friend ostream& operator << (ostream &out, Mint &rhs) {return out << to_string(rhs.x);}
    Mint inv() {return Mint(fp(x, -1));}
    Mint pow(int k) {return Mint(fp(x, k));}
    Mint pow(const Mint &t) {return Mint(fp(x, t.x));}
};


const int maxn = (int) 2e5 + 20;
const int maxm = (int) 2e6 + 20;


LL T[maxn << 2];
int f[maxn << 2];
int s[maxn << 2];

void build(int l, int r, int id)
{
    T[id] = 0;
    f[id] = 0;
    s[id] = r - l + 1;

    if(l == r) return ;
    int mid = MID(l, r);
    build(lson);
    build(rson);
}

void lazy(int id)
{
    if(f[id])
    {
        int v = f[id];
        f[id] = 0;

        f[ls] += v;
        T[ls] += (LL) v * s[ls];

        f[rs] += v;
        T[rs] += (LL) v * s[rs];
    }
}

void update(int L, int R, int v, int l, int r, int id)
{
    if(L <= l && r <= R)
    {
        T[id] += (LL) v * s[id];
        f[id] += v;
        return ;
    }
    lazy(id);

    int mid = MID(l, r);

    if(L <= mid) update(L, R, v, lson);
    if(mid < R) update(L, R, v, rson);

    T[id] = T[ls] + T[rs];
}

LL query(int L, int R, int l, int r, int id)
{
    if(L <= l && r <= R) return T[id];

    lazy(id);
    int mid = MID(l, r);

    if(R <= mid) return query(L, R, lson);
    if(mid < L) return query(L, r, rson);
    return query(L, R, lson) + query(L, R, rson);

}

void work()
{
    int n;
    cin >>n;
    vector<pii> e(n - 1);
    for(int i = 0; i < n - 1; i++) read(e[i].fi, e[i].se);

    vector<vector<int>> G(n + 1);
    for(auto pr : e)
    {
        int x, y;
        depair(x, y, pr);
        if(x < y) swap(x, y);
        G[x].pb(y);
    }
    for(int i = 1; i <= n; i++) sort(rall(G[i]));

    vector<int> dsu(n + 1);
    for(int i = 1; i <= n; i++) dsu[i] = i;

    function<int(int)> find_p = [&](int x)
    {
        if(dsu[x] == x) return x;
        return dsu[x] = find_p(dsu[x]);
    };

    build(1, n, 1);
    LL ans = 0;
    for(int i = 1; i <= n; i++)
    {
        update(1, i, 1, 1, n, 1);

        for(auto x : G[i])
        {
            int pi = find_p(i);
            int px = find_p(x);

            if(pi == px) continue;

            update(1, x, -1, 1, n, 1);
            dsu[pi] = px;
        }

        ans += query(1, i, 1, n, 1);
    }
    cout <<ans <<endl;

}

int main()
{
#ifdef yukihana0416
freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
#endif // yukihana0416

    int tc = 1;
//    read(tc);
    for(int ca = 1; ca <= tc; ca++)
    {
//        printf("Case #%d: ", ca);
        work();
    }
    return 0;
}










Measured memory_bytes: 24168