import scala.io._
object Main{
	def main(args: Array[String]) {
		//val input = Source.fromInputStream(System.in)
		//val lines = input.getLines.toSeq
		val lines = Seq(
		"abc",
		"def",
		"hij"
		)
		println(lines(0)(0).toString+lines(1)(1).toString+lines(2)(2).toString)
	}
}