#include <bits/stdc++.h> 
using namespace std;
#define ll long long
#define in inline
#define re register
const int N = 2e3+10;
const ll mod = 998244353;

in ll read(){
    ll x = 0,f = 1;char c = getchar();
    for(;c < '0' || c > '9';c = getchar())if(c == '-')f = -1;
    for(;c >= '0' && c <= '9';c = getchar())x = (x<<1) + (x<<3) + c-'0';
    return x * f;
}


int n,K;
struct edge{
    int ver,nx;ll ed;
}e[N<<1];
int hd[N],tot;
in void link(int x,int y,ll z){e[++tot] = {y,hd[x],z};hd[x] = tot;}

int siz[N],fa[N];
ll f[N][N];
in void dp(int x){
    f[x][0] = f[x][1] = 0;siz[x] = 1;
    for(re int i = hd[x];i;i = e[i].nx){
        int y = e[i].ver;
        if(y == fa[x])continue;
        fa[y] = x,dp(y),siz[x] += siz[y];
    }
    for(re int i = hd[x];i;i = e[i].nx){
        int y = e[i].ver;
        if(y == fa[x])continue;
        for(re int j = min(K,siz[x]);j >= 0;j--)
            for(re int k = 0;k <= min(j,siz[y]);k++)
                if(f[x][j-k] >= 0)f[x][j] = max(f[x][j],f[x][j-k] + f[y][k] + (ll)(k * (K - k) + (siz[y] - k) * (n - K - siz[y] + k)) * e[i].ed);
    }
}

int main(){
    freopen("haoi2015_t1.in","r",stdin);
    freopen("haoi2015_t1.out","w",stdout);
    n = read(),K = read();
    for(int i = 1;i < n;i++){
        int x = read(),y = read();ll z = read();
        link(x,y,z),link(y,x,z);
    }
    memset(f,-0x3f,sizeof f);
    dp(1);
    printf("%lld\n",f[1][K]);

    
    return 0;
    
}