#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define ll long long
#define PII pair<int, int>
#define pi acos(-1.0)

struct LCA {
    vector<vector<int>> G;
    vector<vector<int>> fa;
    vector<int> dep;
    LCA(int n)
    {
        G.resize(n + 1);
        fa.resize(n + 1, vector<int>(31, 0));
        dep.resize(n + 1, 0);
    }

    void dfs(int u, int f)
    {
        fa[u][0] = f;
        dep[u] = dep[f] + 1;
        for (int i = 1; i < 31; i++) {
            fa[u][i] = fa[fa[u][i - 1]][i - 1];
        }
        for (int v : G[u]) {
            if (v != f) {
                dfs(v, u);
            }
        }
    }

    int lca(int x, int y)
    {
        if (dep[x] < dep[y]) {
            swap(x, y);
        }
        int d = dep[x] - dep[y];
        for (int i = 0; (1 << i) <= d; i++) {
            if ((d >> i) & 1) x = fa[x][i];
        }
        if (x == y) return x;
        for (int i = log2(dep[y]); i >= 0; i--) {
            if (fa[x][i] != fa[y][i]) {
                x = fa[x][i];
                y = fa[y][i];
            }
        }
        return fa[x][0];
    }
    bool isfa(int x, int y) { return lca(x, y) == x; }

    int dist(int x, int y) { return dep[x] + dep[y] - 2 * dep[lca(x, y)]; }
};

int main()
{
    ios::sync_with_stdio(false), cin.tie(nullptr);
    int n, m, q;
    cin >> n >> m >> q;
    LCA T(n);
    vector<int> b(m + 1);
    for (int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;
        T.G[u].push_back(v), T.G[v].push_back(u);
    }
    for (int i = 1; i <= m; i++) cin >> b[i];
    T.dfs(1, 0);
    vector<bool> son(m + 1, false);
    son[1] = 1;
    auto calc = [&](int i) {
        if (i > 2 && T.lca(b[i - 2], b[i]) != b[i - 1] && T.isfa(b[i - 1], b[i - 2]) && T.isfa(b[i - 1], b[i])) return false;
        return T.isfa(b[i - 1], b[i]);
    };
    for (int i = 2; i <= m; i++) {

        son[i] = calc(i);
    }
    // for (int i = 2; i <= m; i++) {
    //     cout << son[i] << " \n"[i == m];
    // }
    int ans = m;
    for (int i = 2; i <= m; i++) {
        if (son[i] == 1 && i != 2) ans--;
    }
    // cout << ans << endl;
    while (q--) {
        int p, w;
        cin >> p >> w;
        unordered_map<int, bool> tmp;
        for (int i = max(2, p - 2); i <= min(m, p + 2); i++) tmp[i] = son[i];
        b[p] = w;
        for (int i = max(2, p - 2); i <= min(m, p + 2); i++) {
            son[i] = calc(i);
        }
        // for (int i = 2; i <= m; i++) {
        //     cout << son[i] << " \n"[i == m];
        // }
        // int ans = m;
        // for (int i = 2; i <= m; i++) {
        //     if (son[i] == 1 && i != 2) ans--;
        // }
        for (int i = max(3, p - 2); i <= min(m, p + 2); i++) {
            ans -= son[i] - tmp[i];
        }
        cout << ans << endl;
    }
    return 0;
}