N = gets.to_i
E = Hash.new { |h, k| h[k] = [] }

(N - 1).times do
  a, b = gets.split.map(&:to_i)
  E[a] << b
  E[b] << a
end

cnt = E.map { |_, list| list.size }.count { |x| x >= 3 }
if cnt >= 2
  puts 'No'
  exit
elsif cnt == 0
  puts 'Yes'
  exit
end

root = (1..N).find { |v| E[v].size >= 3 }
counter = Hash.new(0)

def dfs(v, dist, counter, parent = -1)
  if dist > 0 && E[v].size == 1
    counter[dist] += 1
  end

  E[v].each do |u|
    next if u == parent
    dfs(u, dist + 1, counter, v)
  end
end

dfs(root, 0, counter)

if counter.size >= 2
  puts 'No'
else
  puts 'Yes'
end