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#include<bits/stdc++.h> using namespace std;
typedef long long ll; typedef __int128 int128; typedef pair<int , int > pii; typedef unsigned long long ull;
namespace FastIO { template<typename T> inline T read(T& x) { x = 0; int f = 1; char ch; while (!isdigit(ch = getchar())) if (ch == '-') f = -1; while (isdigit(ch)) x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar(); x *= f; return x; } template<typename T, typename... Args> inline void read(T& x, Args &...x_) { read(x); read(x_...); return; } inline ll read() { ll x; read(x); return x; } }; using namespace FastIO;
const int N = 5e5 + 10;
template<int N, int M> class Graph { private : struct Edge { int to, nt, wt; Edge() {} Edge(int to, int nt, int wt) : to(to), nt(nt), wt(wt) {} }e[M]; int hd[N], cnte; public : inline void AddEdge(int u, int v, int w = 0) { e[++cnte] = Edge(v, hd[u], w); hd[u] = cnte; } inline int head(int u) { return hd[u]; } inline int nt(int u) { return e[u].nt; } inline int to(int u) { return e[u].to; } inline int wt(int u) { return e[u].wt; } };
int n, m; Graph< N , N > G; char ch[N]; struct Qiz { int h, id; Qiz() {} Qiz(int h, int id) : h(h), id(id) {} }; vector<Qiz >qs[N];
inline void Input() { read(n, m); int x; for(int i = 2; i <= n; i++) { read(x); G.AddEdge(x, i); } scanf("%s", ch + 1); int v, h; for(int i = 1; i <= m; i++) { read(v, h); qs[v].push_back(Qiz(h, i)); } }
int sz[N], sn[N], dep[N]; int cnt[N][26]; bool ans[N], vis[N];
inline void Dfs(int u, int fa) { dep[u] = dep[fa] + 1; sz[u] = 1; for(int i = G.head(u); i; i = G.nt(i)) { int v = G.to(i); if(v == fa) continue; Dfs(v, u); sz[u] += sz[v]; if(sz[v] > sz[sn[u]]) sn[u] = v; } }
inline void Insert(int u, int fa, int f) { if(f == 1) cnt[dep[u]][ch[u] - 'a']++; else cnt[dep[u]][ch[u] - 'a'] = 0; for(int i = G.head(u); i; i = G.nt(i)) { int v = G.to(i); if(v == fa || vis[v]) continue; Insert(v, u, f); } }
inline bool Check(int d) { int ans = 0; for(int i = 0; i < 26; i++) { ans += (cnt[d][i] & 1); } return ans <= 1; }
inline void Dfs2(int u, int fa, int flag) { for(int i = G.head(u); i; i = G.nt(i)) { int v = G.to(i); if(v == fa || v == sn[u]) continue; Dfs2(v, u, 0); } if(sn[u]) Dfs2(sn[u], u, 1), vis[sn[u]] = 1; Insert(u, fa, 1); if(sn[u]) vis[sn[u]] = 0; for(auto &p : qs[u]) { ans[p.id] = Check(p.h); } if(!flag) Insert(u, fa, -1); }
inline void Work() { Dfs(1, 0); Dfs2(1, 0, 0); for(int i = 1; i <= m; i++) { if(ans[i]) printf("YES\n"); else printf("NO\n"); } }
int main() { int T = 1; while(T--) { Input(); Work(); } return 0; }
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