#include <bits/stdc++.h>
using namespace std;

#define int long long

const int N = 200005;

int n, k, ans;
vector<int> adj[N];

map<int,int>* dfs(int u, int p) {

    auto *mp = new map<int,int>();
    (*mp)[0] = 1;

    for (int v : adj[u]) {

        if (v == p) continue;

        auto *child = dfs(v, u);

        // luôn merge nhỏ vào lớn
        if (mp->size() < child->size())
            swap(mp, child);

        // đếm đáp án
        for (auto [d, f] : *child) {

            int need = k - d - 1;

            if (mp->count(need))
                ans += 1LL * f * (*mp)[need];
        }

        // merge
        for (auto [d, f] : *child) {
            (*mp)[d + 1] += f;
        }
    }

    return mp;
}

signed main() {

    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> n >> k;

    for (int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;

        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    dfs(1, 0);

    cout << ans;
}