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, paths: &Vec<Vec<(usize, usize)>>, depth: &mut usize, dists: &mut Vec<usize>) {
    dists[cur] = *depth;
    for &(v, _) in paths[cur].iter() {
        if v == prev { continue; }
        *depth += 1;
        dfs(v, cur, paths, depth, dists);
        *depth -= 1;
    }
}

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 tries = paths.iter().filter(|&v| v.len() > 2).count();
    if tries == 0 {
        println!("Yes");
        return;
    } else if tries > 1 {
        println!("No");
        return;
    }
    let (start, end, _) = tree_diameter(&paths);
    let mut dists = vec![0usize; n];
    for &i in vec![start, end].iter() {
        let mut depth = 0usize;
        dfs(i, i, &paths, &mut depth, &mut dists);
        if dists.iter().enumerate().filter(|&(j, _)| i != j && paths[j].len() == 1).map(|(_, &v)| v).collect::<HashSet<usize>>().len() > 1 {
            println!("No");
            return;
        }
    }
    println!("Yes");
}