#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
inline int read() {
  int x = 0;
  char ch = getchar();
  while (!isdigit(ch)) ch = getchar();
  while (isdigit(ch)) {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return x;
}
inline int qpow(int x, long long y) {
  long long r = 1, k = x % MOD;
  for (; y; y >>= 1) {
    if (y & 1) r *= k, r %= MOD;
    k *= k, k %= MOD;
  }
  return r;
}
int main() {
  int n = read(), x = read();
  vector<long long> dat, v;
  dat.reserve(n + 1);
  long long sum = 0;
  for (int i = 1; i <= n; i++) dat[i] = read(), sum += dat[i];
  for (int i = 1; i <= n; i++) v.push_back(sum - dat[i]);
  sort(v.begin(), v.end(), greater<int>());
  while (1) {
    long long cur = v[v.size() - 1], cnt = 0;
    while (v.size() && v[v.size() - 1] == cur) cnt++, v.pop_back();
    if (cnt % x) {
      printf("%d\n", qpow(x, min(sum, cur)));
      return 0;
    } else {
      cnt /= x;
      for (int i = 1; i <= cnt; i++) v.push_back(cur + 1);
    }
  }
}
