#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<vector>
#include<set>
#define REP(i,a,b) for(int i=a;i<=b;i++)
#define MS0(a) memset(a,0,sizeof(a))using namespace std;typedef long long ll;
const int maxn=1000100;
const int INF=1e9+10;int N;
ll L,W;
int p;ll w;
struct Edge
{int v;ll w;
};Edge e[maxn*2];int tot;
int first[maxn],Next[maxn*2];
bool vis[maxn];
struct PLL
{ll l,w;friend bool operator<(PLL A,PLL B){return A.l==B.l?A.w<B.w:A.l<B.l;}
};PLL d[maxn];int dn;
int rt,balance;void Init()
{tot=0;memset(first,-1,sizeof(first));
}void addedge(int u,int v,ll w)
{e[++tot]={v,w};Next[tot]=first[u];first[u]=tot;
}int get_rt(int u,int f,int sz)
{int cnt=1,balance1=0;for(int i=first[u];~i;i=Next[i]){int v=e[i].v;if(v==f||vis[v]) continue;int tmp=get_rt(v,u,sz);cnt+=tmp;balance1=max(balance1,tmp);}balance1=max(balance1,sz-cnt);if(balance1<balance){rt=u;balance=balance1;}return cnt;
}void dfs_d(int u,int f,ll len,ll sw)
{d[++dn]={len,sw};for(int i=first[u];~i;i=Next[i]){int v=e[i].v;ll w=e[i].w;if(v==f||vis[v]) continue;dfs_d(v,u,len+1,sw+w);}
}///---Treap
struct Node
{int ch[2];int v;int r;int sz;
};Node tr[4*maxn];int tot1;
int s[maxn],tot2;
int root;int newnode()
{int k;if(tot2) k=s[tot2--];else k=++tot1;tr[k].ch[0]=tr[k].ch[1]=-1;tr[k].v=0;tr[k].r=rand();tr[k].sz=1;return k;
}void up(int o)
{tr[o].sz=1;if(~tr[o].ch[0]) tr[o].sz+=tr[tr[o].ch[0]].sz;if(~tr[o].ch[1]) tr[o].sz+=tr[tr[o].ch[1]].sz;
}void rot(int &o,int d)
{int k=tr[o].ch[d^1];tr[o].ch[d^1]=tr[k].ch[d];tr[k].ch[d]=o;up(o);up(k);o=k;
}void Insert(int &o,ll x)
{if(o==-1){o=newnode();tr[o].v=x;return;}int d=x<tr[o].v?0:1;Insert(tr[o].ch[d],x);if(tr[tr[o].ch[d]].r>tr[o].r) rot(o,d^1);up(o);
}void Del(int &o,ll x)
{if(o==-1) return;if(tr[o].v==x){if(tr[o].ch[0]==-1) s[++tot2]=o,o=tr[o].ch[1];else if(tr[o].ch[1]==-1) s[++tot2]=o,o=tr[o].ch[0];else{int d=tr[tr[o].ch[0]].r>tr[tr[o].ch[1]].r?0:1;rot(o,d^1);Del(tr[o].ch[d^1],x);}if(~o) up(o);return;}if(x<tr[o].v) Del(tr[o].ch[0],x);else Del(tr[o].ch[1],x);up(o);
}ll query(int o,ll x)
{if(o==-1) return 0;if(x<tr[o].v) return query(tr[o].ch[0],x);ll ls=tr[o].ch[0]==-1?0:tr[tr[o].ch[0]].sz;return ls+1+query(tr[o].ch[1],x);
}ll calc(int u,int f,ll len,ll sw)
{dn=0;dfs_d(u,f,len,sw);sort(d+1,d+dn+1);ll res=0;root=-1;tot1=tot2=0;REP(i,1,dn) Insert(root,d[i].w);for(int l=1,r=dn;l<r;l++){while(r>l&&d[l].l+d[r].l>L) Del(root,d[r].w),r--;Del(root,d[l].w);res+=query(root,W-d[l].w);}return res;
}ll solve(int u)
{rt=u,balance=INF;int sz=get_rt(u,0,N);rt=u,balance=INF;get_rt(u,0,sz);u=rt;vis[u]=1;ll res=0;res+=calc(u,0,0,0);for(int i=first[u];~i;i=Next[i]){int v=e[i].v;ll w=e[i].w;if(vis[v]) continue;res-=calc(v,u,1,w);}for(int i=first[u];~i;i=Next[i]){int v=e[i].v;ll w=e[i].w;if(vis[v]) continue;res+=solve(v);}return res;
}int main()
{//test();return 0;freopen("in.txt","r",stdin);while(cin>>N>>L>>W){Init();REP(i,1,N-1){scanf("%d%I64d",&p,&w);addedge(p,i+1,w);addedge(i+1,p,w);}MS0(vis);printf("%I64d\n",solve(1));}return 0;
}