N = gets.to_i
graph = Array.new(N) { [] }
degrees = [0] * N
(N - 1).times do
    u, v = gets.split.map { |x| x.to_i - 1 }
    graph[u] << v
    graph[v] << u
    degrees[u] += 1
    degrees[v] += 1
end

case degrees.count { |d| d > 2 }
when 0
    puts "Yes"
when 1
    center = degrees.index { |d| d > 2 }
    dists = [nil] * N
    dists[center] = 0
    queue = [center]
    until queue.empty?
        u = queue.shift
        graph[u].each do |v|
            next if dists[v]
            dists[v] = dists[u] + 1
            queue << v
        end
    end
    puts ((0 ... N).filter_map { |i| degrees[i] == 1 && dists[i] }.uniq.size == 1) ? "Yes" : "No"
else
    puts "No"
end