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

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr), cout.tie(nullptr);
	int n, m, q;
	cin >> n >> m >> q;
	vector<vector<int>> e(n + 1);
	for (int i = 1; i < n; i++) {
		int u, v;
		cin >> u >> v;
		e[u].emplace_back(v);
		e[v].emplace_back(u);
	}
	vector<int> dep(n + 1);
	vector<vector<int>> fa(21, vector(n + 1, 0));
	auto dfs = [&](auto &&self, int v, int f) -> void {
		fa[0][v] = f;
		for (auto u : e[v]) {
			if (u != f) {
				dep[u] = dep[v] + 1;
				self(self, u, v);
			}
		}
	};
	for (int i = 1; i <= 20; i++) {
		for (int j = 1; j <= n; j++) {
			fa[i][j] = fa[i - 1][fa[i - 1][j]];
		}
	}
	auto jump = [&](int v, int k) {
		for (int i = 0; i <= 20; i++) {
			if ((k >> i) & 1) {
				v = fa[i][v];
			}
		}
		return v;
	};
	dfs(dfs, 1, 1);
	auto isfa = [&](int u, int v) {
		return dep[u] <= dep[v] && jump(v, dep[v] - dep[u]) == u;
	};
	auto check = [&](int x, int v, int y) {
		if (isfa(v, x)) {
			return isfa(y, v) || !isfa(v, y);
		}
		if (isfa(v, y)) {
			return isfa(x, v) || !isfa(v, x);
		}
		return false;
	};
	vector<int> b(m + 1);
	for (int i = 1; i <= m; i++) {
		cin >> b[i];
	}
	int cnt = m;
	for (int i = 2; i < m; i++) {
		if (check(b[i - 1], b[i], b[i + 1])) {
			--cnt;
		}
	}
	auto calc = [&](int i) {
		int res = 0;
		if (i >= 3 && check(b[i - 2], b[i - 1], b[i])) {
			++res;
		}
		if (i >= 2 && i < m && check(b[i - 1], b[i], b[i + 1])) {
			++res;
		}
		if (i < m - 1 && check(b[i], b[i + 1], b[i + 2])) {
			++res;
		}
		return res;
	};
	for (int i = 1; i <= q; i++) {
		int p, w;
		cin >> p >> w;
		cnt += calc(p);
		b[p] = w;
		cnt -= calc(p);
		cout << cnt << '\n';
	}
	return 0;
}