s<(?:^|\D)(1 [a-z]+(?:, 1 [a-z]+)*)>{
    my @ranks = $1 =~ /[a-z]+/g;
    " a " . join( ', ', @ranks )
}ge;
s/^ //;
if ( /,.+,/ ) {
    s/(.+),([^,]+)/$1, and$2/;
}
print