#include <bits/stdc++.h>
using namespace std;
const int N = 200050;
long long Paths[5][2];
void Set(int x, int y) {
  Paths[x][0] += y;
  Paths[x][1]++;
}
vector<int> Tree[N];
int NodeSize[N];
bool vis[N];
void DFS(int cur, int prev, int &n) {
  n++;
  NodeSize[cur] = 1;
  int i;
  for (i = 0; i < Tree[cur].size(); i++) {
    int v = Tree[cur][i];
    if (v != prev && !vis[v]) {
      DFS(v, cur, n);
      NodeSize[cur] += NodeSize[v];
    }
  }
}
int Find(int cur, int prev, int n) {
  int i;
  for (i = 0; i < Tree[cur].size(); i++) {
    int v = Tree[cur][i];
    if (v != prev && !vis[v]) {
      if (NodeSize[v] > n / 2) return Find(v, cur, n);
    }
  }
  return cur;
}
int Find(int src) {
  int n = 0;
  DFS(src, src, n);
  return Find(src, src, n);
}
long long sol;
int k;
void UpdateSol(int j, int l) {
  int i;
  for (i = 0; i < k; i++) {
    sol += Paths[i][0];
    sol += Paths[i][1] * l;
    if (j + i == 0)
      sol += 0;
    else if (j + i <= k)
      sol += Paths[i][1];
    else
      sol += Paths[i][1] * 2;
  }
}
vector<int> back;
void Solve(int cur, int prev, int path) {
  UpdateSol(path % k, path / k);
  back.push_back(path);
  int i;
  for (i = 0; i < Tree[cur].size(); i++) {
    int v = Tree[cur][i];
    if (v != prev && !vis[v]) {
      Solve(v, cur, path + 1);
    }
  }
}
void Decompose(int src) {
  src = Find(src);
  vis[src] = true;
  int i, j;
  for (i = 0; i < k; i++) Paths[i][0] = 0, Paths[i][1] = 0;
  Set(0, 0);
  for (i = 0; i < Tree[src].size(); i++) {
    int v = Tree[src][i];
    if (!vis[v]) {
      Solve(v, src, 1);
      for (j = 0; j < back.size(); j++) Set(back[j] % k, back[j] / k);
      back.clear();
    }
  }
  for (i = 0; i < Tree[src].size(); i++) {
    int v = Tree[src][i];
    if (!vis[v]) Decompose(v);
  }
}
int main() {
  int n, i, u, v;
  scanf("%i %i", &n, &k);
  for (i = 1; i < n; i++) {
    scanf("%i %i", &u, &v);
    Tree[u].push_back(v);
    Tree[v].push_back(u);
  }
  Decompose(1);
  printf("%lld\n", sol);
  return 0;
}
