my %hash = (
    4 => 20,    
    2 => 40,    
    3 => 30,
    1 => 50,
    5 => 10,
);

while{

my $a = ((sort values %hash));

# key based on the second highest value
my $b = ((sort { $hash{$b} <=> $hash{$a} } keys %hash));

print $b = $a;

}