#include <bits/stdc++.h>
using namespace std;
const double eps = 1.0e-9;
const unsigned long long MAX_N = 100001;
const unsigned long long MAX_M = 1000001;
const long long mod_val = 1000000007;
long long gcd(long long a, long long b) {
  if (a < b) swap(a, b);
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long pow_mod(long long base, long long val) {
  if (val == 1) {
    return base % mod_val;
  } else if (val == 0) {
    return 1;
  }
  long long num = 1;
  if (val % 2 == 1) num = base;
  long long t = pow_mod(base, val / 2);
  t = (t * t) % mod_val;
  num = (num * t) % mod_val;
  return num;
}
long long vals[MAX_N];
int main(int argc, char** argv) {
  std::ios::sync_with_stdio(false);
  long long n, x, val, sum = 0;
  cin >> n >> x;
  map<long long, long long> bits;
  for (unsigned int i = 0; i < (unsigned long long)(n); ++i) {
    cin >> vals[i];
    sum += vals[i];
  }
  for (unsigned int i = 0; i < (unsigned long long)(n); ++i) {
    bits[sum - vals[i]]++;
  }
  map<long long, long long>::iterator iter;
  iter = bits.begin();
  while (iter != bits.end()) {
    val = iter->first;
    if (iter->second >= x) {
      bits[val + 1] += iter->second / x;
    }
    iter->second = iter->second % x;
    iter = bits.lower_bound(val + 1);
  }
  bool isFind = false;
  long long min_bit;
  for (iter = bits.begin(); iter != bits.end(); iter++) {
    if (iter->second != 0) {
      if (!isFind) {
        min_bit = iter->first;
        break;
      }
    }
  }
  val = pow_mod(x, min(min_bit, sum)) % mod_val;
  cout << val << endl;
  return 0;
}
