#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <stack>
#include <array>
#include <list>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;

int main()
{
    int n; ll k; cin>>n>>k;
    ll a[100010];
    for(int i=n-1; i>=0; i--) cin>>a[i];
    ll s=0;
    for(int i=0; i<n; i++) s+=a[i];
    ll ans=0;
    for(int i=n-1; i>=0; i--){
        ans*=k;
        ans+=a[i];
        ans%=s;
    }
    cout<<ans<<endl;
    return 0;
}