CF293E

#include<bits/stdc++.h>

using namespace std;

#define gc c=getchar()
#define r(x) read(x)
#define ll long long

template<typename T>
inline void read(T&x){
    x=0;T k=1;char gc;
    while(!isdigit(c)){if(c=='-')k=-1;gc;}
    while(isdigit(c)){x=x*10+c-'0';gc;}x*=k;
}

const int N=1e5+7;

int n,L,W;

int ecnt;
int fir[N],nex[N<<1],to[N<<1],w[N<<1];

inline void addedge(int u,int v,int c){
    nex[++ecnt]=fir[u],fir[u]=ecnt,to[ecnt]=v,w[ecnt]=c;
    nex[++ecnt]=fir[v],fir[v]=ecnt,to[ecnt]=u,w[ecnt]=c;
}

int SIZE,root;
int s[N];
int siz[N];
bool vis[N];

void getroot(int x,int f){
    siz[x]=1;
    s[x]=0;
    for(int i=fir[x];i;i=nex[i]){
        int v=to[i];
        if(v==f||vis[v])continue;
        getroot(v,x);
        siz[x]+=siz[v];
        s[x]=max(s[x],siz[v]);
    }
    s[x]=max(s[x],SIZE-siz[x]);
    if(s[x]<s[root])root=x;
}

pair<int,int>tmp[N];
int tot;

void getdist(int x,int f,int dis,int dep){
    //if(dis>W||dep>L)return ;
    tmp[++tot]=make_pair(dis,dep);
    for(int i=fir[x];i;i=nex[i]){
        int v=to[i];
        if(v==f||vis[v])continue;
        getdist(v,x,dis+w[i],dep+1);
    }
}

int c[N];

inline void insert(int x){
    for(int i=x+1;i<=n+1;i+=(i&-i))c[i]++;
}

inline void erase(int x){
    for(int i=x+1;i<=n+1;i+=(i&-i))c[i]--;
}

inline ll query(int x){
    if(x<0)return 0;
    ll ret=0;
    for(int i=x+1;i;i^=(i&-i))ret+=c[i];
    return ret;
}

inline ll calc(int x,int v,int d){
    tot=0;
    getdist(x,0,v,d);
    sort(tmp+1,tmp+tot+1);
    for(int i=1;i<=tot;++i){
        insert(tmp[i].second);
    }
    int l=1,r=tot;
    ll sum=0;
    while(l<r){
        if(tmp[l].first+tmp[r].first<=W){
            erase(tmp[l].second);
            sum+=query(L-tmp[l].second);
            ++l;
        }
        else {
            erase(tmp[r].second);
            --r;
        }
    }
    erase(tmp[l].second);
    return sum;
}

ll ans;

void solve(int x,int size){
    ans+=calc(x,0,0);
    vis[x]=1;
    for(int i=fir[x];i;i=nex[i]){
        int v=to[i];
        if(vis[v])continue;
        ans-=calc(v,w[i],1);
        s[root=0]=SIZE=(siz[v]>siz[x]?size-siz[x]:siz[v]);
        getroot(v,0);
        solve(root,SIZE);
    }
}

int main(){
//  freopen(".in","r",stdin);
//  freopen(".out","w",stdout);
    r(n),r(L),r(W);
    for(int i=2;i<=n;++i){
        int v,w;r(v),r(w);
        addedge(i,v,w);
    }
    s[root]=SIZE=n;
    getroot(1,0);
    solve(root,n);
    cout<<ans;
    return 0;
}