#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<map>
#include<vector>
#include <valarray>
#include <cmath>
#include <numeric>
#include <random>
#include <set>

using namespace std;

#define ll long long
//#define int ll

const int maxN = 2e5+10, mod = 998244353, inf = 1e9+10;
int n, m, q, b[maxN], fa[maxN][30], dep[maxN];

ll power(ll x, ll y){
    ll an = 1;
    while(y){
        if (y&1) an = an*x % mod;
        y >>= 1;
        x = x*x %mod;
    }
    return an;
}

ll inv(ll x){
    return power(x, mod-2);
}

vector<int> v[maxN];
set<int> s;

void dfs(int x, int last, int d){
    dep[x] = d;
    fa[x][0] = last;
    for (auto i:v[x]){
        if (i == last) continue;
        dfs(i, x, d+1);
    }
}

int lca(int x, int y){
    if (dep[x] > dep[y]) swap(x, y);
    int z = dep[y]-dep[x], c = 0;
    while (z){
        if (z & 1) y = fa[y][c];
        z >>= 1;
        c++;
    }
    if (x == y) return x;
    for (int i = 20; i >= 0; --i) {
        if (fa[x][i] == fa[y][i]) continue;
        x = fa[x][i];
        y = fa[y][i];
    }
    return fa[x][0];
}

bool is_fa(int son, int f){
    if (son == f) return false;
    return lca(son, f) == f;
}

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

bool check(int x, int y, int on){
    return dis(x, on)+ dis(y, on) == dis(x, y);
}

void solve(){
    cin >> n >> m >> q;
    int x, y;
    for (int i = 1; i < n; ++i) {
        cin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for (int i = 1; i <= m; ++i) cin >> b[i];
    dfs(1, 0, 1);
    for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= 20; ++j) {
            fa[i][j] = fa[fa[i][j-1]][j-1];
        }
    }
    for (int i = 1; i <= m; ++i) {
        if (s.size() <= 1) s.insert(i);
        else{
            auto j = s.rbegin();
            j++;
            if (check(b[*j], b[i], b[*s.rbegin()])) s.erase(*s.rbegin());
            s.insert(i);
        }
    }
    while (q--){
        cin >> x >> y;
        if (m == 1 || m == 2){
            cout << m << "\n";
            continue;
        }

        if (x == 1){
            auto i = s.begin();
            i++;
            auto j = s.begin();
            j++;j++;
            b[x] = y;
            if (!check(b[*i], b[x], b[x+1])) s.insert(x+1);
            else if(check(b[*j], b[x], b[*i])) s.erase(*i);
            cout << s.size() << "\n";
        }else if (x == n){
            auto i = s.rbegin();
            i++;
            auto j = s.rbegin();
            j++;j++;
            b[x] = y;
            if (!check(b[*i], b[x], b[x-1])) s.insert(x-1);
            else if(check(b[*j], b[x], b[*i])) s.erase(*i);
            cout << s.size() << "\n";
        }else{
            if (check(b[x-1], b[x+1], b[x])){
                if (!check(b[x-1], b[x+1], y)) s.insert(y);
            }else{
                auto i1=s.begin();
                while(*i1<x) i1++;
                i1--;
                auto i2=i1;
                i2--;
                auto j1=i1;
                j1++;
                j1++;
                auto j2=j1;
                j2++;
                b[x] = y;
                if (!check(b[*i1], b[x], b[x-1])) s.insert(x-1);
                else if(check(b[*i2], b[x], b[*i1])) s.erase(*i1);
                if (!check(b[*j1], b[x], b[x+1])) s.insert(x+1);
                else if(check(b[*j2], b[x], b[*j1])) s.erase(*j1);
            }
            b[x] = y;
            cout << s.size() << "\n";
        }
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie();
    int t = 1;
    while (t--) solve();
    return 0;
}