win = [[0,1,2,],[3,4,5,],[6,7,8],[0,3,6],[1,4,7],[2,5,8],[0,4,8],[2,4,6]]

while line = gets
s = line.chomp.split("")
flag = "d"
win.each do |a,b,c|
  if s[a] != "s" && s[a] == s[b] && s[b] == s[c]
    flag = s[a]
  end
end
puts flag
end
