#include <bits/stdc++.h>
using namespace std;
const int N = 2e5;
long long bp(long long a, long long b) {
  if (b == 0) return 1;
  long long c = bp(a, b / 2);
  c = (c * c) % 1000000007;
  if (b % 2) c = (c * a) % 1000000007;
  return c;
}
int n;
long long X, sum, a[N];
multiset<long long> second;
int main() {
  scanf("%d%I64d", &n, &X);
  for (int i = 1; i <= n; i++) {
    scanf("%I64d", &a[i]);
    sum += a[i];
  }
  for (int i = 1; i <= n; ++i) second.insert(sum - a[i]);
  long long ans = sum;
  while (!second.empty()) {
    int k = 1;
    long long x = *second.begin();
    second.erase(second.find(x));
    while (!second.empty() && *second.begin() == x) {
      k++;
      second.erase(second.find(x));
    }
    if (k % X != 0) {
      ans = min(ans, (long long)x);
      break;
    }
    k /= X;
    for (int i = 0; i < k; i++) second.insert(x + 1);
  }
  ans = bp(X, ans);
  printf("%I64d", ans);
  return 0;
}
