s = gets.chomp
ma = 0
arr = [""]
s.scan(/([^ｗ]*)(ｗ++)/){|a|
  next if a[0] == ""
  if ma < a[1].length
    ma = a[1].length
    arr = []
  end
  if ma == a[1].length
    arr << a[0]
  end
}
puts arr