// -*- coding:utf-8-unix -*- // #![feature(map_first_last)] #![allow(dead_code)] #![allow(unused_imports)] #![allow(unused_macros)] // use core::num; use std::cmp::*; use std::fmt::*; use std::hash::*; use std::iter::FromIterator; use std::*; use std::{cmp, collections, fmt, io, iter, ops, str}; const INF: i64 = 1223372036854775807; const UINF: usize = INF as usize; const LINF: i64 = 2147483647; const INF128: i128 = 1223372036854775807000000000000; const MOD1: i64 = 1000000007; const MOD9: i64 = 998244353; const MOD: i64 = MOD9; // const MOD: i64 = MOD2; const UMOD: usize = MOD as usize; const M_PI: f64 = 3.14159265358979323846; // use proconio::input; // const MOD: i64 = INF; use cmp::Ordering::*; use std::collections::*; use std::io::stdin; use std::io::stdout; use std::io::Write; macro_rules! p { ($x:expr) => { //if expr println!("{}", $x); }; } macro_rules! vp { // vector print separate with space ($x:expr) => { println!( "{}", $x.iter() .map(|x| x.to_string()) .collect::>() .join(" ") ); }; } macro_rules! d { ($x:expr) => { eprintln!("{:?}", $x); }; } macro_rules! yn { ($val:expr) => { if $val { println!("Yes"); } else { println!("No"); } }; } macro_rules! map{ // declear btreemap ($($key:expr => $val:expr),*) => { { let mut map = ::std::collections::BTreeMap::new(); $( map.insert($key, $val); )* map } }; } macro_rules! set{ // declear btreemap ($($key:expr),*) => { { let mut set = ::std::collections::BTreeSet::new(); $( set.insert($key); )* set } }; } fn main() { solve(); } // use str::Chars; #[allow(dead_code)] fn read() -> T { let mut s = String::new(); std::io::stdin().read_line(&mut s).ok(); s.trim().parse().ok().unwrap() } #[allow(dead_code)] fn read_vec() -> Vec { read::() .split_whitespace() .map(|e| e.parse().ok().unwrap()) .collect() } #[allow(dead_code)] fn read_mat(n: u32) -> Vec> { (0..n).map(|_| read_vec()).collect() } #[allow(dead_code)] fn readii() -> (i64, i64) { let mut vec: Vec = read_vec(); (vec[0], vec[1]) } #[allow(dead_code)] fn readiii() -> (i64, i64, i64) { let mut vec: Vec = read_vec(); (vec[0], vec[1], vec[2]) } #[allow(dead_code)] fn readuu() -> (usize, usize) { let mut vec: Vec = read_vec(); (vec[0], vec[1]) } #[allow(dead_code)] fn readff() -> (f64, f64) { let mut vec: Vec = read_vec(); (vec[0], vec[1]) } fn readcc() -> (char, char) { let mut vec: Vec = read_vec(); (vec[0], vec[1]) } fn readuuu() -> (usize, usize, usize) { let mut vec: Vec = read_vec(); (vec[0], vec[1], vec[2]) } #[allow(dead_code)] fn readiiii() -> (i64, i64, i64, i64) { let mut vec: Vec = read_vec(); (vec[0], vec[1], vec[2], vec[3]) } #[allow(dead_code)] fn readuuuu() -> (usize, usize, usize, usize) { let mut vec: Vec = read_vec(); (vec[0], vec[1], vec[2], vec[3]) } fn read_imat(h: usize) -> Vec> { (0..h).map(|_| read_vec()).collect() } fn read_cmat(h: usize) -> Vec> { (0..h).map(|_| read::().chars().collect()).collect() } fn solve() { let n: usize = read(); let mut graph = vec![vec![(0 as usize, 0 as usize); (0) as usize]; (n) as usize]; let mut es = vec![]; for i in 0..n - 1 { let (mut a, mut b) = readuu(); a -= 1; b -= 1; graph[a].push((b, 1)); graph[b].push((a, 1)); es.push((a, b)); } let mut res = 0; for i in 0..n { let x = graph[i].len() as i64; res += x; res += x * (x - 1); } for e in es { if graph[e.0].len() == 0 || graph[e.1].len() == 0 { continue; } res += ((graph[e.0].len() - 1) * (graph[e.1].len() - 1)) as i64 * 2; } p!(res / 2); return; }