#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 5, mod = 1e9 + 7;
long long a[N], x, n, sum;
long long fastpower(long long b, long long p) {
  if (p == 0) return 1;
  long long halfpower = fastpower(b, p / 2) % mod;
  halfpower *= halfpower;
  halfpower %= mod;
  if (p % 2) halfpower = (halfpower * (b % mod)) % mod;
  return halfpower;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin >> n >> x;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    sum += a[i];
  }
  map<long long, long long> mp;
  for (int i = 0; i < n; i++) mp[sum - a[i]]++;
  for (auto i : mp) {
    mp[i.first + 1] += (i.second / x);
    if (i.second % x) {
      cout << fastpower(x, min(i.first, sum));
      return 0;
    }
  }
}
