#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  int n, k;
  cin >> n >> k;
  vector<ll> a(n);
  rep(i, n) cin >> a[i];
  ll m = accumulate(a.begin(), a.end(), 0LL);
  ll ans = 0;
  rep(i, n) {
    ans = (ans * k + a[i]) % m;
  }
  cout << ans << endl;
  return 0;
}