open all files
grab all lines from file 1 - split each line into 3 strings( $number, $year, $string)
concatenate $number.$year into one $searchvalue
make hash with keys of $searchvalue and values of $string 
populate array1 with these $searchvalues
grab all lines from file 2 into array2
compare array1 to array2
where value from array1 doesn't find a match in file2, print hash value with the key of $searchvalue to file results