Write a PHP program to find the maximum sum of a contiguous subsequence from a given sequence of numbers a1, a2, a3, ... an. A subsequence of one element is also a continuous subsequence

<?php
while($line = fgets(STDIN)){
	$n = intval($line);
	if($n == 0){
		break;
	}	
	$arr = array();
	$max_val = array();
	for($i = 0; $i < $n; $i++){
		$x = intval(fgets(STDIN));
		$arr[$i] = 0;
		$max_val[$i] = -1000000;
		for($j = 0; $j <= $i; $j++){
			$arr[$j] += $x;
			if($max_val[$j] < $arr[$j]){
				$max_val[$j] = $arr[$j];
			}
		}
	}
	
	echo max($max_val)."\n";
}
?>