#include<cstdio>
#include<cmath>
#include<iostream>
#include<cstring>
#include<algorithm>
using namespace std;
typedef long long ll;
struct Edge{int next,to;}ed[6010];
int n,p,q,num_edge,head[3010],dis[3010],dep[3010],fa[3010][21],cnt[3010],sum[3010],cul[3010];
ll ans;
bool vis[3010];
void Add(int f,int t)
{
ed[++num_edge].next=head[f];
ed[num_edge].to=t;
head[f]=num_edge;
}
void Pre(int x,int dept,int dist)
{
vis[x]=1;
dep[x]=dept;
dis[x]=dist;
for(int i=1;i<=13;i++)
{
fa[x][i]=fa[fa[x][i-1]][i-1];
}
for(int i=head[x];i;i=ed[i].next)
{
int t=ed[i].to;
if(vis[t]) continue;
fa[t][0]=x;
Pre(t,dept+1,dist+1);
}
vis[x]=0;
}
int LCA(int x,int y)
{
if(dep[x]<dep[y])
{
swap(x,y);
}
for(int i=13;i>=0;i--)
{
if(dep[fa[x][i]]>=dep[y]) x=fa[x][i];
if(x==y) return x;
}
for(int i=13;i>=0;i--)
{
if(fa[x][i]!=fa[y][i])
{
x=fa[x][i];
y=fa[y][i];
}
}
return fa[x][0];
}
void Cul(int x)
{
vis[x]=1;
for(int i=head[x];i;i=ed[i].next)
{
int t=ed[i].to;
if(vis[t]) continue;
Cul(t);
sum[x]+=sum[t];
cul[x]+=cul[t];
}
sum[x]+=cnt[x];
vis[x]=0;
}
void FPX(int x,int lian,int num,int ffa)
{
if(num==p)
{
lian-=cnt[x];
int lca=LCA(ffa,x);
ans+=(sum[lca]+lian);
ans+=(sum[1]-sum[lca]-cul[lca]);
return;
}
vis[x]=1;
for(int i=head[x];i;i=ed[i].next)
{
int t=ed[i].to;
if(vis[t]) continue;
FPX(t,lian-cnt[x],num+1,ffa);
}
vis[x]=0;
}
int main()
{
scanf("%d%d%d",&n,&p,&q);
for(int i=1;i<=n-1;i++)
{
int f,t;
scanf("%d%d",&f,&t);
Add(f,t);
Add(t,f);
}
Pre(1,1,0);
for(int i=1;i<=n;i++)
{
for(int j=i+1;j<=n;j++)
{
int lca=LCA(i,j);
if(dis[i]+dis[j]-2*dis[lca]==q)
{
cnt[lca]+=2;
cul[i]+=2;
cul[j]+=2;
cul[lca]-=4;
}
}
}
Cul(1);
for(int i=1;i<=n;i++)
{
FPX(i,0,0,i);
}
printf("%lld",ans);
return 0;
}