func main()
	var s: [][]char :: #[3][]char
	for i(0, 2)
		do s[i] :: cui@input()
	end for
	var ans: bool :: true
	for i(0, 2)
		for j(0, 2)
			if(i <> 2 & s[i][j] = s[i + 1][j] | j <> 2 & s[i][j] = s[i][j + 1])
				do ans :: false
				break i
			end if
		end for
	end for
	do cui@print((ans ?("Yes", "No")) ~ "\n")
end func