open FH,"<d:/a.txt";
while(<FH>){
	if(m/^1.*/){
		$line=$_;
		print;
		next;
	}
	if(m/^6.*/){
		@t=split;
		if($temp eq ""){
			$temp=$t[3];
			print;
		}
		else{
			if(!($t[3] eq $temp)){
				print $line;
				print $_;
				$temp=$t[3];
			}	
			else{
				print;
			}		
		}
	}
	else{print;}
}