#include <bits/stdc++.h>
using namespace std;
template <typename T>
void rd(T& x) {
  int f = 0, c;
  while (!isdigit(c = getchar())) f ^= !(c ^ 45);
  x = (c & 15);
  while (isdigit(c = getchar())) x = x * 10 + (c & 15);
  if (f) x = -x;
}
template <typename T>
void pt(T x, int c = 10) {
  if (x < 0) putchar('-'), x = -x;
  if (x > 9) pt(x / 10, -1);
  putchar(x % 10 + 48);
  if (c != -1) putchar(c);
}
template <typename T>
void umax(T& x, const T& y) {
  if (x < y) x = y;
}
template <typename T>
void umin(T& x, const T& y) {
  if (x > y) x = y;
}
using vi = vector<int>;
using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<long, long>;
const int inf = 0x3f3f3f3f;
const int maxn = 2e5 + 5;
const int mod = 1e9 + 7;
int n, k;
vector<int> g[maxn];
ll f[maxn];
int siz[maxn];
int h[maxn][5];
ll sum = 0;
void dfs(int u, int pre) {
  siz[u] = 1;
  h[u][0] = 1;
  f[u] = 0;
  for (auto v : g[u]) {
    if (v == pre) continue;
    dfs(v, u);
    int t[5];
    ll ff = f[v] + h[v][k - 1];
    for (int i = 1; i < k; i++) t[i] = h[v][i - 1];
    t[0] = h[v][k - 1];
    sum += f[u] * siz[v] + ff * siz[u];
    for (int i = 0; i < k; i++)
      for (int j = 0; j < k; j++) {
        if (i + j == 0) continue;
        if (i + j <= k)
          sum += 1LL * h[u][i] * t[j];
        else
          sum += 2LL * h[u][i] * t[j];
      }
    siz[u] += siz[v];
    f[u] += ff;
    for (int i = 0; i < k; i++) h[u][i] += t[i];
  }
}
int main() {
  ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  cin >> n >> k;
  for (int i = 1; i <= n - 1; i++) {
    int u, v;
    cin >> u >> v;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  dfs(1, 0);
  cout << sum << "\n";
  return 0;
}
