#include <iostream>
#include <vector>
#include <array>
#include <algorithm>
#include <functional>
using namespace std;

int main() {
    int n, m, q;
    cin >> n >> m >> q;
    vector<int> head(n + 1), nxt(n * 2), to(n * 2);
    for (int i = 1; i < n; ++i) {
        int u, v; cin >> u >> v;
        to[i * 2] = v;
        nxt[i * 2] = head[u];
        head[u] = i * 2;
        to[i * 2 + 1] = u;
        nxt[i * 2 + 1] = head[v];
        head[v] = i * 2 + 1;
    }
    vector<int> depth(n + 1);
    vector<array<int, 20>> fa(n + 1);
    function<void(int)> build_tree = [&](int cur) {
        for (int e = head[cur]; e; e = nxt[e]) {
            int u = to[e];
            if (u != fa[cur][0]) {
                fa[u][0] = cur;
                depth[u] = depth[cur] + 1;
                for (int i = 0; fa[u][i]; i++)
                    fa[u][i + 1] = fa[fa[u][i]][i];
                build_tree(u);
            }
        }
    };
    build_tree(1);
    vector<int> b(m);
    for (int i = 0; i < m; ++i)
        cin >> b[i];
    vector<bool> is_target(m);
    int cnt = 0;
    function lca = [&](int u, int v) {
        if (depth[u] < depth[v]) swap(u, v);
        for (int i = 19; i >= 0; --i)
            if (1 << i <= u - v) u = fa[u][i];
        if (u == v) return u;
        for (int i = 19; i >= 0; --i)
            if (fa[u][i] != fa[v][i]) { u = fa[u][i]; v = fa[v][i]; }
        return fa[u][0];
    };
    function update = [&](int i) {
        cnt -= is_target[i];
        if (i == 0 || i == m - 1) is_target[i] = true;
        else {
            int A = b[i - 1], B = b[i], C = b[i + 1];
            int R = lca(A, C);
            if (depth[B] >= depth[R] && (lca(A, B) == B || lca(B, C) == B)) is_target[i] = false;
            else is_target[i] = true;
        }
        cnt += is_target[i];
    };
    for (int i = 0; i < m; ++i)
        update(i);
    for (int i = 0; i < q; ++i) {
        int p, w; cin >> p >> w;
        --p;
        b[p] = w;
        if (p > 0) update(p - 1);
        update(p);
        if (p < m - 1) update(p + 1);
        cout << cnt << '\n';
    }
}