#! /usr/bin/perl -w
use 5.014;
use feature 'unicode_strings';
use strict;
use warnings;
use Unicode::Normalize;

my $string = "\x{c3}\x{a9}";
my $decomposed = NFD( $string );
$decomposed =~ s/\pM//g;
$decomposed = NFC( $decomposed );
print length($decomposed)."\n";
print "$decomposed\n";

------------------
~# ./test.pl
2
A?