#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 j = 1; j <= 20; ++j) {
        for (int i = 1; i <= n; ++i) {
            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;
        }
        b[x]=y;
        auto i=s.lower_bound(x);
        i--;
        if(i!=s.begin()) i--;
        if(i!=s.begin()) i--;
        if(i!=s.begin()) i--;
        s.insert(x);
        if(x!=1) s.insert(x-1);
        if(x!=m) s.insert(x+1);
        for(int PO=0;PO < 10;PO++){
            if(i==s.end()) break;
            auto j=i;
            j++;
            if(j==s.end()) break;
            auto k=j;
            k++;
            if(k==s.end()) break;
            if(check(b[*i], b[*k], b[*j])) s.erase(*j);
            else i++;
        }
        printf("%d\n",(int)s.size());
    }
}

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