#include <bits/stdc++.h>
#define int long long
using namespace std;
int const mxN = 2e5+5;
int const mxR = 25005;
vector<int> adj [mxN];
int in[mxN], out[mxN], t, r , n, region[mxN], q, fin[505][505], cnt[505];
vector<pair<int,int>> reg [mxR];
void dfs ( int i, int p ) {
in[i] = t;
t++;
for(auto it:adj[i]){
if(it==p) continue;
dfs(it,i);
}
t++;
out[i] = t;
reg[region[i]].push_back({in[i],out[i]});
}
void dfs2 ( int i, int p ) {
for(int j=1; j<=r; j++) {
if(region[i]==j) continue;
fin[j][region[i]] += cnt[j];
}
cnt[region[i]]++;
for(auto it:adj[i]){
if(it==p) continue;
dfs2(it,i);
}
cnt[region[i]]--;
}
signed main() {
ios_base:: sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
cin>>n>>r>>q>>region[1];
for(int i=2; i<=n; i++) {
int k, h; cin>>k>>h;
adj[i].push_back(k), adj[k].push_back(i);
region[i] = h;
}
if(r>500) dfs(1,0);
else dfs2(1,0);
for(int i=1; i<=r; i++) sort(reg[i].begin(),reg[i].end());
for(int i=0; i<q; i++) {
int x,y; cin>>x>>y;
int ans = 0;
if(r<=500) { cout<<fin[x][y]<<endl; continue; }
for(auto it:reg[x]) {
int ind1 = lower_bound(reg[y].begin(),reg[y].end(), it ) - reg[y].begin();
int ind2 = lower_bound(reg[y].begin(),reg[y].end(), make_pair(it.second, 0ll) ) - reg[y].begin();
ans += ind2-ind1;
}
cout<<ans<<endl;
}
return 0;
}
