$loss=0;
$turn=1;
$bet=1000;
$target=10000;
$multiplier=10;
$p=1/18;
$q=17/18;
$limit=shift;

while ($turn<=$limit) {

$l=int($loss+0.5);
$b=int($bet+0.5);

print "At turn $turn you have lost $l lire so far and must bet $b\n";

$turn++;
$loss+=$bet;
$bet=($loss+$target)/$multiplier;
}

$l=int($loss+0.5);
$loss_prob=$q**$limit;
print "If you lose all the above, you've lost $l\n";
print "The probability of this happening is $loss_prob\n";
print "The rest of the time you win $target\n";
$average_loss=int(-$target*(1-$loss_prob)+$loss*$loss_prob+0.5);
print "So on average you lose $average_loss lire.\n";