#include<bits/stdc++.h>
#define maxn 20
using namespace std;

const int N = 200010, M = N << 1;
int b[N], dph[N];
int h[M], e[M], ne[M], idx = 1;
int n, m, q;
int fa[N][maxn];

void add(int a, int b)
{
	e[idx] = b, ne[idx] = h[a], h[a] = idx++;
}

void dfs(int u, int father)
{
	fa[u][0] = father;
	for (int i = h[u]; i; i = ne[i])
	{
		int v = e[i];
		if (v == father) continue;
		dph[v] = dph[u] + 1;
		dfs(v, u);
	}
}

int lca(int a, int b)
{
	if (dph[a] < dph[b]) swap(a, b);
	int t = dph[a] - dph[b];
	for (int i = maxn - 1; i >= 0; --i)
		if (t >> i & 1) a = fa[a][i];
	if (a == b) return a;
	else {
		for (int i = maxn - 1; i >= 0; --i)
			if (fa[a][i] != fa[b][i])
				a = fa[a][i], b = fa[b][i];
		return fa[a][0];
	}
}

int dist(int a, int b)
{
	int p = lca(a, b);
	return dph[a] + dph[b] - dph[p] * 2;
}

int checklink(int l, int p, int r)
{
	int dis1 = dist(l, p);
	int dis2 = dist(p, r);
	int dis3 = dist(l, r);
	return ((dis1 + dis2) == dis3);
}

int init() // 修改前的答案
{
	if (m <= 2) return m;
	
	int ans = 2;
	for (int i = 2; i < m; ++i)
		if (!checklink(b[i - 1], b[i], b[i + 1])) ans++;
	return ans;
}

int main()
{
	cin >> n >> m >> q;
	for (int i = 1; i < n; ++i)
	{
		int a, b;
		cin >> a >> b;
		add(a, b), add(b, a);
	}
	for (int i = 1; i <= m; ++i) cin >> b[i];
	
	dfs(1, 0);
	
	for (int i = 2; i <= n; ++i)
		for (int j = 1; j < maxn; ++j)
			fa[i][j] = fa[fa[i][j - 1]][j - 1];
	
	int res = init();
//	printf("res0=%d\n", res);
	int pos = 0, x = 0;
	for (int _ = 0; _ < q; ++_)
	{
		cin >> pos >> x;
//		if (pos - 2 >= 1)
//		{
//			int st1 = checklink(b[pos - 2], b[pos - 1], b[pos]);
//			int st2 = checklink(b[pos - 2], b[pos - 1], x);
//			res += st1 - st2;
//		}
//		if (pos - 1 >= 1 && pos + 1 <= m)
//		{
//			int st1 = checklink(b[pos - 1], b[pos], b[pos + 1]);
//			int st2 = checklink(b[pos - 1], x, b[pos + 1]);
//			res += st1 - st2;
//		}
//		if (pos + 2 <= m)
//		{
//			int st1 = checklink(b[pos], b[pos + 1], b[pos + 2]);
//			int st2 = checklink(x, b[pos + 1], b[pos + 2]);
//			res += st1 - st2;
//		}
		b[pos] = x;
		res = init();
		cout << res << endl;
	}
	
	return 0;
}