#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
const int N = 3001;
const int N_ = 3000;
const int S = 1000000;
pair<int, int> ejw[N][N], qu[N][N];
int eo[N], cnt[N];
int pp[N], dd[N];
bool used[S + 1], good[N_];
void dfs_dd(int i, int d) {
used[dd[i] = d] = true;
for (int o = 0; o < eo[i]; o++) {
auto jw = ejw[i][o];
int j = jw.first, w = jw.second;
dfs_dd(j, d + w);
}
}
void dfs_qu(int i) {
for (int o = 0; o < eo[i]; o++) {
auto jw = ejw[i][o];
int j = jw.first, w = jw.second;
dfs_qu(j);
for (int z = 0; z < cnt[j]; z++) {
auto hd = qu[j][z];
int h = hd.first, d = hd.second;
qu[i][cnt[i]++] = { 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_++;
pp[0] = -1;
for (int i = 1; i < n; i++) {
int p, w; cin >> p >> w, w++;
ejw[pp[i] = p][eo[p]++] = { i, w };
}
for (int h = 0; h < k; h++) {
int i, d; cin >> i >> d, d++;
qu[i][cnt[i]++] = { h, d };
}
dfs_dd(0, 0);
dfs_qu(0);
for (int i = 0; i < n; i++)
for (int z = 0; z < cnt[i]; z++) {
auto hd = qu[i][z];
int h = hd.first, d = hd.second;
if (dd[i] + d == s_ || s_ >= w_ + d && used[s_ - w_ - d])
good[h] = true;
else if (n <= 501 && k <= 500 && s_ >= dd[i] + d)
for (int p = i; p >= 0; p = pp[p]) {
int s = dd[i] + d, d_ = w_ + dd[i] - dd[p];
if ((s_ - s) % d_ == 0) {
good[h] = true;
break;
}
}
}
for (int h = 0; h < k; h++)
cout << (good[h] ? "YES" : "NO") << '\n';
return 0;
}
