G

#include <iostream>
#include <iomanip>
#include <vector>
#include <array>
#include <set>

using namespace std;

//#define int long long

const long long INF = 1e9 + 7;
const int MAXN = 5e4 + 100;
const int N = 1e5 + 10;
const int MOD = 1e9 + 7;

int n, k;
int dp[MAXN][510];
array<vector<int>, MAXN> g;
int ans = 0;

void dfs(int v, int p) {
    dp[v][0] = 1;
    for (auto to: g[v]) {
        if (to == p) {
            continue;
        }
        dfs(to, v);
        for (int len = 0; len < k; ++len) {
            ans += dp[to][len] * dp[v][k - len - 1];
        }
        for (int len = 0; len <= k; ++len) {
            dp[v][len + 1] += dp[to][len];
        }
    }
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    cin >> n >> k;
    for (int i = 0; i < n - 1; ++i) {
        int u, v;
        cin >> u >> v;
        --u, --v;
        g[u].emplace_back(v);
        g[v].emplace_back(u);
    }
    dfs(0, -1);
    cout << ans << '\n';
}