FNR == 1 {
    getline nextline < FILENAME;
    printf "" > FILENAME ".new";
}
{
    getline nextline < FILENAME;
    if ($0 ~ /^FN: / && nextline !~ /^ORG: /) {
        print $0 >> FILENAME ".new";
        print "ORG: " FILENAME >> FILENAME ".new";
    }
    else if ($0 ~ /^ORG: / && prevline ~ /^FN: /) {
        print substr($0, 1, length($0)-1) " + " FILENAME >> FILENAME ".new";
    }
    else {
        print $0 >> FILENAME ".new";
    }
    prevline = $0;
}