#! perl -slw
use strict;
 use List::Util qw[ reduce ];;

my @array=(1,2,3,4,-1,-2,-3,11,12,13);;
my $sum = @{
    reduce{
        @{ $a } = ( $a->[0]+$b, $b ) if $b > $a->[1];
        $a;
    } [0, -9e99 ], @array
}[0];

print $sum;