// LUOGU_RID: 154919549
//#pragma GCC optimize(3,"Ofast","inline")
#include <bits/stdc++.h>
#define int long long
using ll = long long;
const int M = 5e3 + 3;
//#define int long long
//int a[M];
//long long s[M],f1[M][M * 2],g[M][M * 2];
using namespace std;
const int mod = 1e9 + 7;
//int a[200050];
void solve() {
    int n,m,q;std::cin>>n>>m>>q;
	std::vector<std::vector<int> > e(n + 2), f(n + 2,std::vector<int>(102));
	std::vector<int> dep(2 + n);    
    for(int i = 1;i < n;i++){
        int u,v;std::cin>>u>>v;
        e[u].push_back(v);
        e[v].push_back(u);
    }
    std::vector<int> b(m + 3);
    for(int i = 1;i <= m;i++){
        std::cin>>b[i];
    }
    auto prdfs = [&](auto &&prdfs, int x, int fa) -> void{
		
		f[x][0] = fa;
		dep[x] = dep[fa] + 1;
		
		for(int i = 1;i < 31;i ++){
			f[x][i] = f[f[x][i - 1]][i - 1];
		}
		
		for(auto i : e[x]) {
			if(i == fa)continue;
			prdfs(prdfs, i, x);
		}
	};
	
	auto lca = [&](int u, int v) -> int{
		
		if(dep[u] < dep[v]) std::swap(u,v);
		int dis = dep[u] - dep[v];
		
		int jp = 0;
		while(dis && jp <= 30){
			if(dis % 2)u = f[u][jp];
			dis >>= 1, jp++;
		}
		//std::cout<<dep[u]<<" "<<dep[v]<<" ";
		
		if(u == v) return u;
		
		for(int i = 30;i >= 0 && u != v;i--){
			if(f[u][i] != f[v][i]) u = f[u][i], v = f[v][i];
		}
		
		return f[u][0];
	};

    auto dis = [&](int u, int v) -> int{
        return dep[u] + dep[v] - 2 * dep[lca(u,v)];
    };
    prdfs(prdfs,b[1],0);
    //std::cout<<q<<" ";
    int ans = m;
    std::vector<int> tag(m + 3);
    for(int i = 2;i < m;i++){
        if(dis(b[i],b[i + 1]) + dis(b[i - 1],b[i]) == dis(b[i - 1],b[i + 1])){
            tag[i] = 1;
            ans--;
        }
        
    }
    //for(int i = 1;i <= m;i++){
        //std::cout<<tag[i]<<" ";
    //}
    for(int j = 1;j <= q;j++){
        
        int i,x;std::cin>>i>>x;
        if(tag[i])ans++,tag[i] = 0;
        if(i + 2 <= m)if(tag[i + 1])ans++,tag[i + 1] = 0;
        //if(tag[i - 1])ans++,tag[i - 1] = 0;
        b[i] = x;
        if(dis(b[i],b[i + 1]) + dis(b[i - 1],b[i]) == dis(b[i - 1],b[i + 1])){
            tag[i] = 1;
            ans--;
        }
        if(i + 2 <= m)
        if(dis(b[i],b[i + 1]) + dis(b[i + 1],b[i + 2]) == dis(b[i + 2],b[i])){
            tag[i + 1] = 1;
            ans--;
        }
        std::cout<<ans<<'\n';       
    }

}

signed main() {
    //io::init();
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    int t = 1;
    // std::cin >> t;
    //    init();
    while (t--) {
        solve();
        // std::cout.flush();
    }
    // std::cout<<5 * inv(2ll) % mod<<'\n';
    return 0;
}