/*
public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}*/


public class Solution {
    public ListNode FindFirstCommonNode(ListNode pHead1, ListNode pHead2) {
        ListNode c1 = pHead1;
        ListNode c2 = pHead2;

        while (c1 != c2) {
            c1 = c1 == null ? pHead2 : c1.next;
            c2 = c2 == null ? pHead1 : c2.next;
        }

        return c1;
    }
}