#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const int maxn = 2e5 + 5;
const int INF = 0x7fffffff;
const long long inf = 0x3f3f3f3f;
const double eps = 1e-8;
int n, k;
vector<int> v[maxn];
struct node {
  long long k[6];
  long long num, ct;
} dp[maxn];
int du[maxn], used[maxn];
int main() {
  scanf("%d%d", &n, &k);
  for (int i = 0; i < n - 1; i++) {
    int u, w;
    scanf("%d%d", &u, &w);
    v[u].push_back(w);
    v[w].push_back(u);
    du[u]++;
    du[w]++;
  }
  queue<int> q;
  for (int i = 1; i <= n; i++) {
    if (du[i] == 1) {
      q.push(i);
    }
    dp[i].k[0] = 1;
    dp[i].num = 0;
    dp[i].ct = 1;
  }
  long long ans = 0;
  while (q.size()) {
    int u = q.front();
    q.pop();
    if (used[u]) continue;
    used[u] = 1;
    for (auto i : v[u]) {
      if (used[i] == 1)
        continue;
      else {
        ans += dp[u].num * dp[i].ct + dp[i].num * dp[u].ct;
        ans += dp[u].k[0] * dp[i].k[0];
        for (int j = 0; j < k; j++) {
          for (int l = 0; l < k; l++) {
            if (j + l >= k + 1) {
              ans -= dp[i].k[j] * dp[u].k[l];
            }
          }
        }
        for (int j = 0; j < k; j++) {
          dp[i].k[j] += dp[u].k[(j + 1) % k];
        }
        dp[i].num += dp[u].num + dp[u].k[0];
        dp[i].ct += dp[u].ct;
        du[i]--;
        if (du[i] <= 1 && !used[i]) {
          q.push(i);
        }
      }
    }
  }
  printf("%lld\n", ans);
  return 0;
}
