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//~ while (clock()<=69*CLOCKS_PER_SEC)
//~ #pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("O3")
//~ #pragma GCC optimize("Ofast")
//~ #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//~ #pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>

using namespace std;

using ll=long long;
using ld=long double;
using pii=pair<int, int>;
using pll=pair<ll, ll>;
using vi=vector<int>;
using vll=vector<ll>;

template<class TH> void _dbg(const char *sdbg, TH h){ cerr<<sdbg<<" = "<<h<<endl; }
#ifdef LOCAL
#define _upgrade ios_base::sync_with_stdio(0);
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__);
#else
#define _upgrade ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
#define debug(...) 98;
#define cerr if(0) cout
#endif

#define pb push_back
#define mp make_pair
#define all(x) x.begin(),x.end()
#define sz(x) ((int)(x).size())
#define fi first
#define se second

#define erase_duplicates(x) sort(all(x)), (x).resize(distance((x).begin(), unique(all(x))));

#define watch(x) cout << (#x) << " is " << (x) << endl;

#define pow2(x) ((x)*(x))
#define mod(x, m) ((((x) % (m)) + (m)) % (m))
#define max3(a, b, c) max(a, max(b, c))
#define min3(a, b, c) min(a, min(b, c))

#define REP(i, a, b) for(int i = a; i <= b; ++i)
#define REPV(i, b, a) for(int i = b; i >= a; --i)

const double m_pi = acos(-1.0);
const int int_max = 0x3f3f3f3f;
const int M7 = 1000*1000*1000+7;
const int M9 = 1000*1000*1000+9;

vector<pair<int, int > > tos[30009];
long long npot[100009];

//const long long MOD1 = 1LL*M7*M7;


long long tempvs1;
vector<long long> odls1;

void dfs1(int pos, int ojc, int dziad){
    //odl[dziad][pos]=temp;
    if(dziad<pos)odls1.pb(tempvs1);

    for(int i=0;i<sz(tos[pos]);++i){
        pii too = tos[pos][i];
        if(too.fi == ojc)continue;
        tempvs1+=npot[too.se];
        dfs1(too.fi, pos, dziad);
        tempvs1-=npot[too.se];
    }

}



vector<short> tempvs;
vector<vector<short> > odls;

void dfs2(int pos, int ojc, int dziad){
    //odl[dziad][pos]=temp;
    if(dziad<pos)odls.pb(tempvs);

    for(int i=0;i<sz(tos[pos]);++i){
        pii too = tos[pos][i];
        if(too.fi == ojc)continue;
        tempvs.pb(too.se);
        dfs2(too.fi, pos, dziad);
        tempvs.pop_back();
    }

}

vector<long long> qwe;
int maxp = 0;
int brutq = 0;

int main(){
    _upgrade
    cout<<fixed<<setprecision(15);

    int n, k;cin>>n>>k;


    for(int i=0;i<n-1;++i){
        int a, b, p;
        cin>>a>>b>>p;
        tos[a].pb({b, p});
        tos[b].pb({a, p});
        maxp=max(maxp, p);
    }

    npot[1]=1;
    for(int i=2;i<=max(maxp, 4);++i){
        long long temp = npot[i-1];
        temp*=n;
        if(maxp>4)temp%=M7;
        npot[i]=temp; 
    }

    if(maxp <= 4){
        for(int i=1;i<=n;++i){
            dfs1(i, i, i);
        }
        sort(all(odls1));

        cout<<odls1[k-1]%M7*npot[2]%M7<<"\n";
    }
    else{
        for(int i=1;i<=n;++i){
            dfs2(i, i, i);
        }

        for(int i=0;i<sz(odls);++i){
            sort(all(odls[i]));
            reverse(all(odls[i]));
        }
        sort(all(odls));

        long long www=0;
        for(int i=0;i<sz(odls[k-1]);++i){//cerr<<odls[k-1][i]<<" ";
            www+=npot[odls[k-1][i]];
            www%=M7;
        }//cerr<<endl;

        cout<<www*npot[2]%M7<<"\n";
    }


    return 0;
}




/*
    __builtin_popcount count total set bits on a given integer
    (use __builtin_popcountll for long long).


*/