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
    
    int maxN=-100000;
    int maxRes=-100000;
    while(head!=null){
        maxN=Math.max(maxN+head.val,head.val);
        maxRes=Math.max(maxRes,maxN);
        head=head.next;
    }
    return maxRes;

    }
}