#!/usr/bin/perl

sub interleave {
    my @elems = sort { $$a[1] <=> $$b[1] or $$a[0] cmp $$b[0] }
        ( ["A", $_[0]], ["B", $_[1]] );
    $elems[0][1]-- if $elems[0][1] > 1;
    my $div = sprintf "%d", $elems[1][1] / $elems[0][1];
    my $mod = $elems[1][1] % $elems[0][1];
    if ($mod % 2 == 0) {
        $elems[1][1] -= $mod;
        $mod = $mod / 2;
    } else { $mod = 0 }
    print $elems[0][0] . $elems[1][0] x $mod;
    $elems[0][1]-- if $elems[0][1] == 1;
    until ($elems[0][1] <= 1) {
        print $elems[1][0] x $div . $elems[0][0];
        $elems[0][1]--;
        $elems[1][1] -= $div;
    }
    print $elems[1][0] x $elems[1][1] . $elems[1][0] x $mod .
        $elems[0][0] x $elems[0][1] . "\n";
}

interleave (@ARGV);
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