#!/usr/bin/perl
use 5.026;

my @chars;
my %scores;

@chars = <> =~ /(.)/g;

for my $toDel (0, 'a'..'z') {
    my @curChars = grep {!/($toDel|\u$toDel)/} @chars;

    for (my $i = 0; $i < @curChars - 1; $i++) {
        if ($curChars[$i] eq ($curChars[$i+1] ^ " ")) {
            splice @curChars, $i, 2;
            $i = $i ? $i - 2 : -1;
        }
    }

    say scalar @curChars unless $toDel;
    $scores{$toDel} = scalar @curChars;
}

say ((sort { $scores{$a} <=> $scores{$b} } keys %scores)[0]);