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

#define CPP_STR(x) CPP_STR_I(x)
#define CPP_CAT(x,y) CPP_CAT_I(x,y)
#define CPP_STR_I(args...) #args
#define CPP_CAT_I(x,y) x ## y

using i8  = int8_t;
using u8  = uint8_t;
using i16 = int16_t;
using u16 = uint16_t;
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;

using f32 = float;
using f64 = double;

#define FOR(i, start, end) for(i64 i = (start), CPP_CAT(i,xxxx_end)=(end); i < CPP_CAT(i,xxxx_end); ++i)
#define REP(i, n) FOR(i, 0, n)
#define REPS(i, n) for(i64 i = 1; i <= n; ++i)
#define RREP(i, n) for(i64 i = n - 1; i >= 0 ; --i)
#define RREPS(i, n) for(i64 i = n; i >= 1; --i)

#define ALL(f,c,...) (([&](decltype((c)) cccc) { return (f)(std::begin(cccc), std::end(cccc), ## __VA_ARGS__); })(c))

#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );

#define pb push_back
#define mp make_pair
#define F first
#define S second

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

template<typename C>
i64 SIZE(const C& c) { return static_cast<i64>(c.size()); }

template<typename T, size_t N>
i64 SIZE(const T (&)[N]) { return static_cast<i64>(N); }


struct ProconInit {
    static constexpr int IOS_PREC = 15;
    static constexpr bool AUTOFLUSH = false;

    ProconInit() {
        cin.tie(nullptr);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(IOS_PREC);
        if(AUTOFLUSH)
            cout << unitbuf;
    }
} PROCON_INIT;


#define MAX_N 100'000
vector<i64> G[MAX_N];

template<int MOD>
struct Fp {
    i64 val;
    constexpr Fp(i64 v = 0) noexcept : val(v % MOD) {
        if (val < 0) val += MOD;
    }
    constexpr int getmod() { return MOD; }
    constexpr Fp operator - () const noexcept {
        return val ? MOD - val : 0;
    }
    constexpr Fp operator + (const Fp& r) const noexcept { return Fp(*this) += r; }
    constexpr Fp operator - (const Fp& r) const noexcept { return Fp(*this) -= r; }
    constexpr Fp operator * (const Fp& r) const noexcept { return Fp(*this) *= r; }
    constexpr Fp operator / (const Fp& r) const noexcept { return Fp(*this) /= r; }
    constexpr Fp& operator += (const Fp& r) noexcept {
        val += r.val;
        if (val >= MOD) val -= MOD;
        return *this;
    }
    constexpr Fp& operator -= (const Fp& r) noexcept {
        val -= r.val;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr Fp& operator *= (const Fp& r) noexcept {
        val = val * r.val % MOD;
        return *this;
    }
    constexpr Fp& operator /= (const Fp& r) noexcept {
        i64 a = r.val, b = MOD, u = 1, v = 0;
        while (b) {
            i64 t = a / b;
            a -= t * b; swap(a, b);
            u -= t * v; swap(u, v);
        }
        val = val * u % MOD;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr bool operator == (const Fp& r) const noexcept {
        return this->val == r.val;
    }
    constexpr bool operator != (const Fp& r) const noexcept {
        return this->val != r.val;
    }
    constexpr bool operator > (const Fp& r) const noexcept {
        return this->val > r.val;
    }
    constexpr bool operator >= (const Fp& r) const noexcept {
        return this->val >= r.val;
    }
    friend constexpr ostream& operator << (ostream &os, const Fp<MOD>& x) noexcept {
        return os << x.val;
    }
    friend constexpr Fp<MOD> modpow(const Fp<MOD> &a, i64 n) noexcept {
        if (n == 0) return 1;
        auto t = modpow(a, n / 2);
        t = t * t;
        if (n & 1) t = t * a;
        return t;
    }
};

#define MOD 1'000'000'007
using mint = Fp<MOD>;
i64 N, K;

bool visited[MAX_N];
mint dfs(i64 u, i64 from, i64 k) {
    mint cnt = k;
    i64 nk = 1 + (from < 0 ? 0 : 1);
    for (i64 v : G[u]) {
        if (visited[v]) continue;
        visited[v] = true;
        cnt *= dfs(v, u, K - nk);
        nk++;
    }
    return cnt;
}

int main() {
    cin >> N >> K;
    fill(visited, visited + MAX_N, false);

    i64 u, v;
    REP(i, N - 1) {
        cin >> u >> v;
        u--; v--;
        G[u].pb(v);
        G[v].pb(u);
    }

    i64 s = 0;
    visited[s] = true;
    mint cnt = dfs(s, -1, K);
    cout << cnt << endl;

    return 0;
}

Measured memory_bytes: 10496