#include <bits/stdc++.h>
using namespace std;
const int nm = 100002;
const long long mod = 1000000007;
int n;
long long x;
long long a[nm];
void nhap() {
  scanf("%d%I64d", &n, &x);
  int i;
  for (i = 1; i <= n; ++i) scanf("%I64d", &a[i]);
}
long long power(long long a, long long n) {
  if (!n) return 1;
  long long tg = power(a, n / 2);
  tg = (tg * tg) % mod;
  if (n % 2) tg = (tg * a) % mod;
  return tg;
}
void xuli() {
  long long sum = 0;
  int i;
  for (i = 1; i <= n; ++i) sum += a[i];
  for (i = 1; i <= n; ++i) a[i] = sum - a[i];
  sort(a + 1, a + n + 1);
  int j, k, u;
  i = 1;
  do {
    j = i;
    while (j + 1 <= n && a[j + 1] == a[j]) ++j;
    if ((j - i + 1) % x == 0) {
      k = (j - i + 1) / x;
      for (u = 1; u <= k; ++u) a[j + 1 - u] = a[i] + 1;
      i = j + 1 - k;
    } else {
      printf("%I64d", power(x, min(a[i], sum)));
      return;
    }
  } while (1);
}
int main() {
  nhap();
  xuli();
}
