#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using db = double;
using ld = long double;
using str = string;
template <class T>
using V = vector<T>;
template <class T1, class T2>
using PR = pair<T1, T2>;
template <class T1, class T2>
using umap = unordered_map<T1, T2>;
using pi = PR<int, int>;
using vi = V<int>;
const ll MOD = 1e9 + 7;
ll binexp(ll n, ll k) {
  if (k == 0) return 1;
  ll cur = binexp(n, k / 2) % MOD;
  if (k % 2)
    return ((cur * cur) % MOD * n) % MOD;
  else
    return (cur * cur) % MOD;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n, x;
  cin >> n >> x;
  V<ll> a(n), b(n);
  ll sum = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    sum += a[i];
  }
  for (int i = 0; i < n; i++) b[i] = sum - a[i];
  while (true) {
    ll v = b[b.size() - 1];
    int occ = 0;
    while (b.size() > 0 && b[b.size() - 1] == v) {
      occ++;
      b.pop_back();
    }
    if (occ % x) {
      v = min(v, sum);
      cout << binexp((ll)x, v);
      return 0;
    } else {
      occ /= x;
      for (int i = 0; i < occ; i++) b.push_back(v + 1);
    }
  }
}
