#include <bits/stdc++.h>
using namespace std;
constexpr int mxN = 200069, BSZ = 125; // wtf 125 works??? this is so cringe
int N, R, Q, H[mxN], rgnOrd[mxN>>3], revOrd[mxN>>3];
vector<int> adj[mxN], rgnLst[mxN>>3], rgnLst2[mxN>>3];
int timer, tin[mxN], tout[mxN];
int tdall[BSZ][BSZ], td[mxN][BSZ];
void dfs(int f) {
tin[f] = timer++;
for (int i = 0; i < min(R, BSZ) && revOrd[H[f]] < BSZ; i++) {
tdall[revOrd[H[f]]][i] += td[f][i];
}
for (int nf : adj[f]) {
for (int i = 0; i < min(R, BSZ); i++) {
td[nf][i] = td[f][i] + (rgnOrd[i] == H[f]);
}
dfs(nf);
}
tout[f] = timer-1;
}
signed main() {
scanf("%d%d%d%d", &N, &R, &Q, &H[0]);
rgnLst[--H[0]].push_back(0);
for (int i = 1, p; i < N; i++) {
scanf("%d%d", &p, &H[i]);
adj[--p].push_back(i);
rgnLst[--H[i]].push_back(i);
}
iota(rgnOrd, rgnOrd+R, 0);
sort(rgnOrd, rgnOrd+R, [&](const int &a, const int &b) {
return rgnLst[a].size() > rgnLst[b].size();
});
for (int i = 0; i < R; i++) {
revOrd[rgnOrd[i]] = i;
}
dfs(0);
for (int i = 0; i < R; i++) {
for (int j : rgnLst[i]) {
rgnLst2[i].push_back(tin[j]);
}
sort(rgnLst2[i].begin(), rgnLst2[i].end());
}
for (int a, b, ans; Q--; ) {
scanf("%d%d", &a, &b);
a--, b--;
ans = 0;
if (revOrd[a] < BSZ && revOrd[b] < BSZ) {
ans = tdall[revOrd[b]][revOrd[a]];
} else if (revOrd[a] < BSZ) {
for (int i : rgnLst[b]) {
ans += td[i][revOrd[a]];
}
} else {
for (int i : rgnLst[a]) {
ans += upper_bound(rgnLst2[b].begin(), rgnLst2[b].end(), tout[i]) - lower_bound(rgnLst2[b].begin(), rgnLst2[b].end(), tin[i]);
}
}
printf("%d\n", ans);
fflush(stdout);
}
}
