#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
#include<vector>
using namespace std;
const int N = 2e5 + 5;

int n, m, qr, p, g, b[N], ans;
int fa[N][22], dep[N];
bool f[N];
vector<int> ve[N];

void dfs(int x, int last, int d){
    dep[x] = d;
    fa[x][0] = last;
    for (auto i:ve[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];
}

void check(int i){
    int l = 0, r = 0, z = 0, ret;
    ret = lca(b[i - 1], b[i + 1]);
    if(ret == b[i - 1]) l++;
    else if(ret == b[i + 1]) r++;
    ret = lca(b[i - 1], b[i]);
    if(ret == b[i - 1]) l++;
    else if(ret == b[i]) z++;
    ret = lca(b[i], b[i + 1]);
    if(ret == b[i]) z++;
    else if(ret == b[i + 1]) r++;
    
    if(f[i] == 1){
        if(l == 2 && z == 1) f[i] = 0;
        else if(r == 2 && z == 1) f[i] = 0;
        else if(l == 0 && r == 0 && (z == 1 || (z == 2 && lca(b[i - 1], b[i + 1]) == b[i]) || (z == 2 && lca(lca(b[i - 1], b[i + 1]), b[i]) != b[i]))){
            f[i] = 0;
        }
        if(f[i] == 0) ans--;
    }
    else{
        if(l == 2 && z == 1) f[i] = 0;
        else if(r == 2 && z == 1) f[i] = 0;
        else if(l == 0 && r == 0 && (z == 1 || (z == 2 && lca(b[i - 1], b[i + 1]) == b[i]) || (z == 2 && lca(lca(b[i - 1], b[i + 1]), b[i]) != b[i]))){
            f[i] = 0;
        }
        else{
            f[i] = 1;
            ans++;
        }
    }
}

int main(){
    scanf("%d%d%d", &n, &m, &qr);
    int u, v;
    for(int i = 1; i < n; i++){
        scanf("%d%d", &u, &v);
        ve[u].push_back(v);
        ve[v].push_back(u);
    }
    for(int i = 1; i <= m; i++){
        scanf("%d", &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];
        }
    }
    f[1] = 1;
    f[m] = 1;
    for(int i = 2; i < m; i++){
        int l = 0, r = 0, z = 0, ret;
        ret = lca(b[i - 1], b[i + 1]);
        if(ret == b[i - 1]) l++;
        else if(ret == b[i + 1]) r++;
        ret = lca(b[i - 1], b[i]);
        if(ret == b[i - 1]) l++;
        else if(ret == b[i]) z++;
        ret = lca(b[i], b[i + 1]);
        if(ret == b[i]) z++;
        else if(ret == b[i + 1]) r++;
        
        f[i] = 1;
        if(l == 2 && z == 1) f[i] = 0;
        else if(r == 2 && z == 1) f[i] = 0;
        else if(l == 0 && r == 0 && (z == 1 || (z == 2 && lca(b[i - 1], b[i + 1]) == b[i]) || (z == 2 && lca(lca(b[i - 1], b[i + 1]), b[i]) != b[i]))){
            f[i] = 0;
        }
    }
    ans = 0;
    for(int i = 1; i <= m; i++){
        if(f[i]) ans++;
    }
    
    while(qr--){
        scanf("%d%d", &p, &g);
        b[p] = g;
        if(p > 1 && p < m) check(p);
        if(p - 1 > 1 && p - 1 < m) check(p - 1);
        if(p + 1 > 1 && p + 1 < m) check(p + 1);
        printf("%d\n", ans);
    }
    return 0;
}