// ---------- begin input macro ---------- // reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 macro_rules! input { (source = $s:expr, $($r:tt)*) => { let mut iter = $s.split_whitespace(); input_inner!{iter, $($r)*} }; ($($r:tt)*) => { let s = { use std::io::Read; let mut s = String::new(); std::io::stdin().read_to_string(&mut s).unwrap(); s }; let mut iter = s.split_whitespace(); input_inner!{iter, $($r)*} }; } macro_rules! input_inner { ($iter:expr) => {}; ($iter:expr, ) => {}; ($iter:expr, $var:ident : $t:tt $($r:tt)*) => { let $var = read_value!($iter, $t); input_inner!{$iter $($r)*} }; } macro_rules! read_value { ($iter:expr, ( $($t:tt),* )) => { ( $(read_value!($iter, $t)),* ) }; ($iter:expr, [ $t:tt ; $len:expr ]) => { (0..$len).map(|_| read_value!($iter, $t)).collect::>() }; ($iter:expr, chars) => { read_value!($iter, String).chars().collect::>() }; ($iter:expr, bytes) => { read_value!($iter, String).bytes().collect::>() }; ($iter:expr, usize1) => { read_value!($iter, usize) - 1 }; ($iter:expr, $t:ty) => { $iter.next().unwrap().parse::<$t>().expect("Parse error") }; } // ---------- end input macro ---------- fn run() { input! { n: usize, e: [(usize1, usize1); n - 1], } let mut g = vec![vec![]; n]; for (a, b) in e { g[a].push(b); g[b].push(a); } let mut parent = vec![0; n]; let mut topo = vec![0]; for i in 0..n { let v = topo[i]; for u in g[v].clone() { let x = g[u].iter().position(|p| *p == v).unwrap(); g[u].remove(x); parent[u] = v; topo.push(u); } } let mut size = vec![1usize; n]; let mut ans = 0; for &v in topo.iter().rev() { let mut c = vec![]; for &u in g[v].iter() { size[v] += size[u]; c.push(size[u]); } if size[v] < n { c.push(n - size[v]); } for c in c.iter() { ans += *c * (n - *c); } } ans += n * n; println!("{}", ans); } fn main() { run(); }