#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], power[mxR];
vector<pair<int,int>> reg [mxR], ori[mxR];
vector<vector<int>> seg [mxR];
void build ( int node, int l, int r , int i) {
if(l==r-1) { seg[i][node].push_back(reg[i][l].second); return ; }
int m = (l+r)/2;
build(node*2+1, l, m, i), build(node*2+2, m, r, i);
seg[i][node] = seg[i][node*2+1];
for(auto it:seg[i][node*2+2]) seg[i][node].push_back(it);
sort(seg[i][node].begin(),seg[i][node].end());
}
int get ( int node, int l, int r, int i, int ind , int val) {
if(l>=ind) return 0;
if(r<=ind) {
int tot = seg[i][node].size();
int smaller = lower_bound(seg[i][node].begin(), seg[i][node].end(), val ) - seg[i][node].begin();
return tot - smaller;
}
int m = (l+r)/2;
return get(node*2+1, l, m, i, ind, val) + get(node*2+2, m, r, i, ind, val);
}
void dfs ( int i, int p ) {
t++, in[i] = 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]});
}
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;
}
dfs(1,0);
for(int i=1; i<=r; i++) {
sort(reg[i].begin(),reg[i].end());
ori[i] = reg[i];
int pw = (1<<(__lg(reg[i].size()-1)+1));
power[i] = pw;
for(int j=reg[i].size(); j<=pw; j++) reg[i].push_back({0,0});
seg[i].resize(4*pw+5);
build(0,0,pw, i);
}
for(int i=0; i<q; i++) {
int x,y; cin>>x>>y;
int ans = 0;
if(ori[x].size()<=ori[y].size()) {
for(auto it:ori[x]) {
int ind1 = lower_bound(ori[y].begin(),ori[y].end(), it ) - ori[y].begin();
int ind2 = lower_bound(ori[y].begin(),ori[y].end(), make_pair(it.second, 0ll) ) - ori[y].begin();
ans += ind2-ind1;
}
cout<<ans<<endl; continue;
}
for(auto it:ori[y]){
int ind = lower_bound(ori[x].begin(),ori[x].end(), it ) - ori[x].begin();
ans+=get(0,0,power[x], x, ind, it.second);
}
cout<<ans<<endl;
}
return 0;
}
