#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline void next_int(T &x) {
  x = 0;
  char c;
  bool neg = false;
  while (!isdigit(c = getchar()))
    if (c == '-') neg = true;
  do x = x * 10 + c - 48;
  while (isdigit(c = getchar()));
  if (neg) x = -x;
}
template <typename T>
inline void write_int(T x, char last = 0) {
  if (x < 0) putchar('-'), x = abs(x);
  char tmp[20];
  int cnt = 0;
  while (x >= 10) tmp[cnt++] = x % 10 + 48, x /= 10;
  tmp[cnt] = x + 48;
  for (int i = (cnt); i >= (0); --i) putchar(tmp[i]);
  if (last) putchar(last);
}
struct data {
  long long sum, cnt;
};
const int N = (int)2e5 + 5;
int n, k, sz[N];
data dp[N][6], dp2[N][6], tmp[N][6];
long long ans;
vector<int> g[N];
void dfs(int u, int p) {
  dp[u][0].cnt = sz[u] = 1;
  for (int i = (0); i < (((int)g[u].size())); ++i) {
    int v = g[u][i];
    if (v == p) continue;
    dfs(v, u);
    sz[u] += sz[v];
    if (k == 1) {
      dp[u][0].sum += (dp[v][0].sum + dp[v][0].cnt),
          dp[u][0].cnt += dp[v][0].cnt;
      tmp[v][0].sum = dp[v][0].sum + dp[v][0].cnt, tmp[v][0].cnt = dp[v][0].cnt;
    } else {
      for (int j = (0); j < (k); ++j) {
        if (!j) {
          dp[u][j].sum += dp[v][k - 1].sum, dp[u][j].cnt += dp[v][k - 1].cnt;
          tmp[v][j].sum = dp[v][k - 1].sum, tmp[v][j].cnt = dp[v][k - 1].cnt;
        } else if (j == 1) {
          dp[u][j].sum += (dp[v][0].sum + dp[v][0].cnt),
              dp[u][j].cnt += dp[v][0].cnt;
          tmp[v][j].sum = dp[v][0].sum + dp[v][0].cnt,
          tmp[v][j].cnt = dp[v][0].cnt;
        } else {
          dp[u][j].sum += dp[v][j - 1].sum, dp[u][j].cnt += dp[v][j - 1].cnt;
          tmp[v][j].sum = dp[v][j - 1].sum, tmp[v][j].cnt = dp[v][j - 1].cnt;
        }
      }
    }
  }
}
void dfs_calc(int u, int p) {
  for (int i = (0); i < (k); ++i) ans += (dp[u][i].sum + dp2[u][i].sum);
  for (int i = (0); i < (((int)g[u].size())); ++i) {
    int v = g[u][i];
    if (v == p) continue;
    for (int j = (0); j < (k); ++j)
      dp[u][j].sum -= tmp[v][j].sum, dp[u][j].cnt -= tmp[v][j].cnt;
    if (k == 1) {
      dp2[v][0].sum +=
          (dp[u][0].sum + dp2[u][0].sum + dp2[u][0].cnt + dp[u][0].cnt);
      dp2[v][0].cnt += (dp[u][0].cnt + dp2[u][0].cnt);
    } else {
      for (int j = (0); j < (k); ++j) {
        if (!j) {
          dp2[v][j].sum += (dp[u][k - 1].sum + dp2[u][k - 1].sum);
          dp2[v][j].cnt += (dp[u][k - 1].cnt + dp2[u][k - 1].cnt);
        } else if (j == 1) {
          dp2[v][j].sum +=
              (dp[u][0].sum + dp2[u][0].sum + dp2[u][0].cnt + dp[u][0].cnt);
          dp2[v][j].cnt += (dp[u][0].cnt + dp2[u][0].cnt);
        } else {
          dp2[v][j].sum += (dp[u][j - 1].sum + dp2[u][j - 1].sum);
          dp2[v][j].cnt += (dp2[u][j - 1].cnt + dp[u][j - 1].cnt);
        }
      }
    }
    for (int j = (0); j < (k); ++j)
      dp[u][j].sum += tmp[v][j].sum, dp[u][j].cnt += tmp[v][j].cnt;
    dfs_calc(v, u);
  }
}
int main() {
  next_int(n), next_int(k);
  for (int i = (1); i < (n); ++i) {
    int u, v;
    next_int(u), next_int(v);
    g[u].push_back(v);
    g[v].push_back(u);
  }
  dfs(1, 0);
  dfs_calc(1, 0);
  write_int(ans / 2LL);
  return 0;
}
