import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可
     *
     * 
     * @param head ListNode类 
     * @return int整型
     */
    public int FindGreatestSumOfSubArray (ListNode head) {
        // write code here
        if (null == head.next) {
            return head.val;
        }
        int res = head.val;
        int pre = head.val;
        ListNode node = head.next;
        while (null != node) {
            if (pre <= 0) {
                pre = node.val;
            }
            else {
                pre = pre + node.val;
            }
            res = Math.max(res, pre);
            node = node.next;
        }
        return res;
    }
}