struct DFS {
    graph: Vec<Vec<usize>>,
}

impl DFS {
    fn new(n: usize) -> DFS {
        DFS {
            graph: vec![vec![]; n],
        }
    }

    fn add_edge(&mut self, from: usize, to: usize) {
        self.graph[from].push(to);
    }

    fn search(&mut self, from: usize, d: usize) -> usize {
        let mut res = 0;
        for &to in self.graph[from].clone().iter() {
            res += self.search(to, d + 1);
        }
        res + (1 + d) * d / 2
    }
}

fn main() {
    let n: usize = {
        let mut buf = String::new();
        std::io::stdin().read_line(&mut buf).unwrap();
        buf.trim_end().parse().unwrap()
    };

    let mut dfs = DFS::new(n);
    let mut is_root = vec![true; n];
    for _ in 0..(n - 1) {
        let (a, b): (usize, usize) = {
            let mut buf = String::new();
            std::io::stdin().read_line(&mut buf).unwrap();
            let mut iter = buf.split_whitespace();
            (
                iter.next().unwrap().parse::<usize>().unwrap() - 1,
                iter.next().unwrap().parse::<usize>().unwrap() - 1,
            )
        };
        dfs.add_edge(a, b);
        is_root[b] = false;
    }

    let root = {
        is_root.iter()
            .enumerate()
            .filter(|&(_, &b)| b)
            .map(|(i, _)| i)
            .next()
            .unwrap()
    };

    let ans = dfs.search(root, 0);
    println!("{}", ans);
}