use std::collections::{VecDeque, HashSet};

const INF: usize = 1usize << 60;

fn tree_diameter(paths: &Vec<Vec<(usize, usize)>>) -> (usize, usize, usize) {
    fn calc(paths: &Vec<Vec<(usize, usize)>>, start: usize) -> Vec<usize> {
        let n = paths.len();
        let mut costs = vec![INF; n];
        costs[start] = 0usize;
        let mut deq = VecDeque::new();
        deq.push_back(start);
        while let Some(u) = deq.pop_front() {
            for &(v, cost) in paths[u].iter() {
                if costs[v] < INF { continue; }
                costs[v] = costs[v].min(costs[u] + cost);
                deq.push_back(v);
            }
        }
        costs
    }
    let n = paths.len();
    let costs = calc(paths, 0);
    let idx = costs.into_iter().enumerate().max_by_key(|&(_, c)| c).unwrap().0;
    let costs = calc(paths, idx);
    let ridx = costs.into_iter().enumerate().max_by_key(|&(_, c)| c).unwrap();
    // start_point, end_point, cost
    (idx, ridx.0, ridx.1)
}

fn dfs(cur: usize, prev: usize, depths: &mut usize, paths: &Vec<Vec<(usize, usize)>>, dists: &mut HashSet<usize>) {
    let mut flg = false;
    for &(v, _) in paths[cur].iter() {
        if v == prev { continue; }
        *depths += 1;
        dfs(v, cur, depths, paths, dists);
        *depths -= 1;
        flg = true;
    }
    if !flg {
        dists.insert(*depths);
    }
}

fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    let mut paths = vec![vec![]; n];
    for _ in 0..n-1 {
        let mut temp = String::new();
        std::io::stdin().read_line(&mut temp).ok();
        let temp: Vec<usize> = temp.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
        let a = temp[0]-1;
        let b = temp[1]-1;
        paths[a].push((b, 1));
        paths[b].push((a, 1));
    }

    let size = paths.iter().filter(|&v| v.len() > 2).count();
    if size > 1 {
        println!("No");
        return;
    } else if size == 0 {
        println!("Yes");
        return;
    }
    let (start, end, _) = tree_diameter(&paths);
    let mut depths = 0usize;
    let mut dists = HashSet::new();
    dfs(start, start, &mut depths, &paths, &mut dists);
    dfs(end, end, &mut depths, &paths, &mut dists);
    if dists.len() == 1 {
        println!("Yes");
    } else {
        println!("No");
    }
}