#include <bits/stdc++.h>
using namespace std;
const long long maxn = 100005;
const long long p = 1e9 + 7;
long long a[maxn], n, x, sum;
long long st[maxn], top;
vector<long long> v;
inline long long read() {
  long long x = 0, f = 1;
  char ch = getchar();
  while (!isdigit(ch)) {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (isdigit(ch)) {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return x * f;
}
inline long long qpow(long long x, long long y) {
  long long res = 1;
  while (y) {
    if (y & 1) res = (res * x % p) % p;
    x = (x % p * x % p) % p;
    y >>= 1;
  }
  return res % p;
}
signed main() {
  n = read();
  x = read();
  for (long long i = 1; i <= n; i++) a[i] = read(), sum += a[i];
  for (long long i = 1; i <= n; i++) st[++top] = sum - a[i];
  sort(st + 1, st + n + 1);
  reverse(st + 1, st + n + 1);
  while (1) {
    long long res = st[top], cnt = 0;
    while (top > 0 && res == st[top]) cnt++, top--;
    if (cnt % x) {
      printf("%d", qpow(x, min(sum, res)));
      return 0;
    } else {
      cnt /= x;
      for (long long i = 1; i <= cnt; i++) st[++top] = res + 1;
    }
  }
  return 0;
}
