write a go solution for Description:
In Homer's country, there are n cities numbered 1 to n and they form a tree. That is, there are (n-1) undirected roads between these n cities and every two cities can reach each other through these roads.

Homer's country is an industrial country, and each of the n cities in it contains some mineral resource. The mineral resource of city i is labeled a_i.

Homer is given the plans of the country in the following q years. The plan of the i-th year is described by four parameters u_i,v_i,l_i and r_i, and he is asked to find any mineral resource c_i such that the following two conditions hold:

- mineral resource c_i appears an odd number of times between city u_i and city v_i; and
- l_i<=c_i<=r_i.

As the best friend of Homer, he asks you for help. For every plan, find any such mineral resource c_i, or tell him that there doesn't exist one.

Input Format:
The first line contains two integers n (1<=qn<=q3*10^5) and q (1<=q<=3*10^5), indicating the number of cities and the number of plans.

The second line contains n integers a_1,a_2,...,a_n (1<=a_i<=n).

Then the i-th line of the following (n-1) lines contains two integers x_i and y_i (1<=x_i,y_i<=n) with x_ineqy_i, indicating that there is a bidirectional road between city x_i and city y_i. It is guaranteed that the given roads form a tree.

Then the i-th line of the following q lines contains four integers u_i, v_i, l_i, r_i (1<=u_i<=n, 1<=v_i<=n, 1<=l_i<=r_i<=n), indicating the plan of the i-th year.

Output Format:
Print q lines, the i-th of which contains an integer c_i such that

- c_i=-1 if there is no such mineral resource that meets the required condition; or
- c_i is the label of the chosen mineral resource of the i-th year. The chosen mineral resource c_i should meet those conditions in the i-th year described above in the problem statement. If there are multiple choices of c_i, you can print any of them.

Note:
In the first three queries, there are four cities between city 3 and city 5, which are city 1, city 2, city 3 and city 5. The mineral resources appear in them are mineral resources 1 (appears in city 3 and city 5), 2 (appears in city 2) and 3 (appears in city 1). It is noted that

- The first query is only to check whether mineral source 1 appears an odd number of times between city 3 and city 5. The answer is no, because mineral source 1 appears twice (an even number of times) between city 3 and city 5.
- The second and the third queries are the same but they can choose different mineral resources. Both mineral resources 2 and 3 are available.. Output only the code with no comments, explanation, or additional text.