#include <bits/stdc++.h>
using namespace std;
vector<int> rel[50005];
queue<int> topo;
int nodes, dist, n1, n2, node, totes, rtotes;
int dp[50005][505], vis[50005], parent[50005], nsort[50005];
bool hp(int i, int j) { return vis[i] > vis[j]; }
int main() {
  scanf("%d%d", &nodes, &dist);
  for (int i = 1; i < nodes; i++) {
    scanf("%d%d", &n1, &n2);
    dp[i][0] = 1;
    nsort[i] = i;
    rel[n1].push_back(n2);
    rel[n2].push_back(n1);
  }
  dp[nodes][0] = 1;
  nsort[nodes] = nodes;
  topo.push(1);
  vis[1] = 1;
  while (!topo.empty()) {
    node = topo.front();
    topo.pop();
    for (int i = 0; i < rel[node].size(); i++) {
      if (!vis[rel[node][i]]) {
        parent[rel[node][i]] = node;
        vis[rel[node][i]] = vis[node] + 1;
        topo.push(rel[node][i]);
      }
    }
  }
  sort(nsort + 1, nsort + 1 + nodes, hp);
  for (int i = 1; i <= nodes; i++) {
    node = nsort[i];
    for (int j = 0; j < dist; j++) {
      rtotes += dp[node][j] * dp[parent[node]][dist - j - 1];
    }
    dp[parent[node]][0] = 1;
    for (int j = 0; j <= dist; j++) {
      dp[parent[node]][j + 1] += dp[node][j];
    }
    if (parent[node]) {
      topo.push(parent[node]);
    }
  }
  printf("%d\n", rtotes);
  return 0;
}
