#include<bits/stdc++.h>
using namespace std;

const int N = 1e5 + 5;

vector<int> v[N];
vector<pair<int, int>> query[N];
int colour[N];
int parent[N];

void dfs1(int sv, int par)
{
    parent[sv] = par;
    for(int x : v[sv])
    {
        if(x == par)
        {
            continue;
        }
        dfs1(x, sv);
    }
}

void dfs2(int sv, int & cnt, int col)
{
    cnt += (colour[sv] == col);
    for(int x : v[sv])
    {
        if(x == parent[sv])
        {
            continue;
        }
        dfs2(x, cnt, col);
    }
}

int32_t main()
{
    ios_base:: sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    #ifndef ONLINE_JUDGE
      freopen("input.txt", "r", stdin);
      freopen("output.txt", "w", stdout);
    #endif
    int n, root, query;
    cin >> n >> query >> root;
    for(int i = 0; i < n - 1; i++)
    {
        int a, b;
        cin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for(int i = 1; i <= n; i++)
    {
        cin >> colour[i];
    }
    dfs1(root, 0);
    for(int i = 1; i <= query; i++)
    {
        int node, colour;
        cin >> node >> colour;
        int cnt = 0;
        dfs2(node, cnt, colour);
        cout << cnt << endl;
    }
}