#include <bits/stdc++.h>
using namespace std;
void my_dbg() { cout << endl; }
template <typename Arg, typename... Args>
void my_dbg(Arg A, Args... B) {
  cout << ' ' << A;
  my_dbg(B...);
}
using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
const int inf = INT_MAX;
const int ninf = INT_MIN;
const int mod = 1e9 + 7;
const int maxN = 1e6 + 2;
vi in(maxN), out(maxN), ver(maxN), sz(maxN);
vi val(maxN), lev(maxN), total(maxN), ans(maxN);
vi adj[maxN];
vector<pair<int, int>> q[maxN];
int cnt[maxN][26];
int tim;
void dfs(int node, int par) {
  in[node] = tim;
  sz[node] = 1;
  ver[tim] = node;
  for (int it : adj[node]) {
    if (it != par) {
      tim++;
      lev[it] = lev[node] + 1;
      dfs(it, node);
      sz[node] += sz[it];
    }
  }
  out[node] = tim;
}
void dsu_on_tree(int node, int par, bool keep) {
  int big_child = -1, max_sz = -1;
  for (int it : adj[node]) {
    if (it != par && sz[it] > max_sz) {
      max_sz = sz[it];
      big_child = it;
    }
  }
  for (int it : adj[node]) {
    if (it != par && it != big_child) dsu_on_tree(it, node, 0);
  }
  if (big_child != -1) {
    dsu_on_tree(big_child, node, 1);
  }
  total[lev[node]] -= cnt[lev[node]][val[node]];
  cnt[lev[node]][val[node]] ^= 1;
  total[lev[node]] += cnt[lev[node]][val[node]];
  for (int it : adj[node]) {
    if (it != par && it != big_child) {
      for (int t = in[it]; t <= out[it]; t++) {
        total[lev[ver[t]]] -= cnt[lev[ver[t]]][val[ver[t]]];
        cnt[lev[ver[t]]][val[ver[t]]] ^= 1;
        total[lev[ver[t]]] += cnt[lev[ver[t]]][val[ver[t]]];
      }
    }
  }
  for (auto query : q[node]) {
    int depth = query.first, idx = query.second;
    if (total[depth] > 1)
      ans[idx] = 0;
    else
      ans[idx] = 1;
  }
  if (!keep) {
    for (int t = in[node]; t <= out[node]; t++) {
      total[lev[ver[t]]] -= cnt[lev[ver[t]]][val[ver[t]]];
      cnt[lev[ver[t]]][val[ver[t]]] ^= 1;
      total[lev[ver[t]]] += cnt[lev[ver[t]]][val[ver[t]]];
    }
  }
}
int main() {
  int n, m;
  scanf("%d", &n);
  scanf("%d", &m);
  for (int i = 2; i < (int)n + 1; i++) {
    int p;
    scanf("%d", &p);
    adj[i].push_back(p);
    adj[p].push_back(i);
  }
  for (int i = 1; i < (int)n + 1; i++) {
    char c;
    cin >> c;
    val[i] = c - 'a';
  }
  for (int i = 0; i < (int)m; i++) {
    int v, h;
    scanf("%d", &v);
    scanf("%d", &h);
    q[v].push_back({h, i});
  }
  lev[1] = 1;
  dfs(1, 1);
  dsu_on_tree(1, 1, 1);
  for (int i = 0; i < (int)m; i++) {
    puts(ans[i] ? "Yes" : "No");
  }
  return 0;
}
