### constant

MAX_N = 7

### main

while line = gets
  n = line.strip.to_i

  nodes = MAX_N.times.map{false}
  nbrs = MAX_N.times.map{[]}
  start = nil

  for dmn in gets.strip.split(' ')
    ai = dmn[0].to_i
    bi = dmn[1].to_i

    start = ai
    nodes[ai] = nodes[bi] = true

    if ai != bi
      nbrs[ai] << bi
      nbrs[bi] << ai
    end
  end

  reached = MAX_N.times.map{false}
  reached[start] = true

  q = [start]

  while ! q.empty?
    u = q.shift

    for v in nbrs[u]
      if ! reached[v]
        reached[v] = true
        q << v
      end
    end
  end

  ok = true
  odd_n = 0

  for i in (0...MAX_N)
    if nodes[i] && ! reached[i]
      ok = false
      break
    end
    if (nbrs[i].length & 1) == 1
      odd_n += 1
    end
  end

  ok = false if odd_n > 2

  puts (ok ? 'Yes' : 'No')
end