#include <bits/stdc++.h>
using namespace std;
long long mod = 1000000000 + 7;
void fun() {}
long long bpow(long long x, long long v) {
  if (v == 0) return 1 % mod;
  if (v % 2 == 1) return (x * bpow(x, v - 1)) % mod;
  long long r = bpow(x, v / 2);
  return (r * r) % mod;
}
signed main() {
  fun();
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long n, x;
  cin >> n >> x;
  long long a[n];
  long long sum = 0;
  vector<long long> power;
  for (long long i = 0; i < n; i++) {
    cin >> a[i];
    sum += a[i];
  }
  for (long long i = 0; i < n; i++) {
    power.push_back(sum - a[i]);
  }
  sort(power.rbegin(), power.rend());
  long long mn = power.back();
  long long i;
  while (1) {
    long long cnt = 0;
    mn = power.back();
    while (!power.empty() && power.back() == mn) {
      power.pop_back();
      cnt++;
    }
    if ((cnt % x) != 0) {
      if (mn > sum) mn = sum;
      cout << bpow(x, mn);
      return 0;
    }
    cnt = cnt / x;
    for (long long i = 0; i < cnt; i++) power.push_back(mn + 1);
  }
}
