#include <bits/stdc++.h>
using namespace std;
const int base = 1e9;
const int maxn = 1e3;
const int logn = 20;
const int inf = 2e9;
const int alpha = 26;
const int my_hash = 29;
const long long l_inf = 4e18;
const long long mod = 1e9 + 7;
const double pi = acos(-1.0);
const double eps = 1e-9;
int n;
long long x, sum = 0;
vector<long long> a, b;
long long binpow(long long a, long long b) {
  if (!b) return 1;
  if (b % 2) return (binpow(a, b - 1) * a) % mod;
  long long k = binpow(a, b / 2);
  return (k * k) % mod;
}
int main() {
  ios_base::sync_with_stdio();
  cin >> n >> x;
  a = vector<long long>(n);
  for (int i = int(0); i < int(n); i++) {
    cin >> a[i];
    sum += a[i];
  }
  for (int i = int(0); i < int(n); i++) b.push_back(sum - a[i]);
  sort(b.rbegin(), b.rend());
  while (true) {
    long long cnt = 0, v = b.back();
    while (!b.empty() && b.back() == v) {
      cnt++;
      b.pop_back();
    }
    if (cnt % x) {
      cout << binpow(x, min(v, sum));
      exit(0);
    } else {
      cnt /= x;
      for (int i = int(0); i < int(cnt); i++) b.push_back(v + 1);
    }
  }
}
