#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
const int N = 3001;
const int N_ = 3000;
const int S = 1000000;
vector<pair<int, int>> ejw[N], qu[N];
int dd[N];
bool used[S + 1], good[N_];
void dfs_dd(int i, int d) {
used[dd[i] = d] = true;
for (auto &jw : ejw[i]) {
int j = jw.first, w = jw.second;
dfs_dd(j, d + w);
}
}
void dfs_qu(int i) {
for (auto &jw : ejw[i]) {
int j = jw.first, w = jw.second;
dfs_qu(j);
for (auto &hd : qu[j]) {
int h = hd.first, d = hd.second;
qu[i].push_back({ h, w + d });
}
}
}
int main() {
ios_base::sync_with_stdio(false), cin.tie(NULL);
int n, k, s_, w_; cin >> n >> k >> s_ >> w_, n++, w_++;
for (int i = 1; i < n; i++) {
int p, w; cin >> p >> w, w++;
ejw[p].push_back({ i, w });
}
for (int h = 0; h < k; h++) {
int i, d; cin >> i >> d, d++;
qu[i].push_back({ h, d });
}
dfs_dd(0, 0);
dfs_qu(0);
for (int i = 0; i < n; i++)
for (auto &hd : qu[i]) {
int h = hd.first, d = hd.second;
if (dd[i] + d == s_ || s_ >= w_ + d && used[s_ - w_ - d])
good[h] = true;
}
for (int h = 0; h < k; h++)
cout << (good[h] ? "YES" : "NO") << '\n';
return 0;
}
