#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:1024000000,1024000000")
using namespace std;
const int maxn = 510005;
int n, m;
vector<int> g[maxn];
char s[maxn];
vector<int> dep[maxn];
vector<int> op[maxn];
int id[maxn][2];
int deep[maxn];
int mx[maxn];
int dfs_clock = 1;
void dfs(int u, int d) {
  deep[u] = mx[u] = d;
  id[u][0] = dfs_clock++;
  dep[d].push_back(1 << (s[u] - 'a'));
  op[d].push_back(id[u][0]);
  for (int i = 0; i < g[u].size(); i++) {
    dfs(g[u][i], d + 1);
    mx[u] = max(mx[u], mx[g[u][i]]);
  }
  id[u][1] = dfs_clock++;
}
int main() {
  int p;
  scanf("%d%d", &n, &m);
  for (int i = 2; i <= n; i++) {
    scanf("%d", &p);
    g[p].push_back(i);
  }
  scanf("%s", s + 1);
  dfs(1, 1);
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j < dep[i].size(); j++) {
      dep[i][j] ^= dep[i][j - 1];
    }
  }
  int u, h;
  for (int i = 0; i < m; i++) {
    scanf("%d%d", &u, &h);
    if (h <= deep[u] || h > mx[u]) {
      printf("Yes\n");
    } else {
      int i = upper_bound(op[h].begin(), op[h].end(), id[u][0]) - op[h].begin();
      int j =
          upper_bound(op[h].begin(), op[h].end(), id[u][1]) - op[h].begin() - 1;
      int a;
      if (i - 1 >= 0)
        a = dep[h][j] ^ dep[h][i - 1];
      else
        a = dep[h][j];
      int num = 0;
      for (int i = 0; i < 26; i++) {
        if (a & (1 << i)) num++;
      }
      if (num <= 1)
        printf("Yes\n");
      else
        printf("No\n");
    }
  }
  return 0;
}
