#include<bits/stdc++.h>
#if __has_include(<atcoder/all>)
#include<atcoder/all>
#endif
// using namespace std;
// using namespace atcoder;
#define int long long
#define rep(i, n) for(int i = 0;i<(int)(n);i++)
#define all(v) (v).begin(),(v).end()
using lint = long long;
using ll = long long;
using P = std::pair<int,int>;

int mod_pow(int n,int k,int mod) {
    int res = 1;
    while(k) {
        if(k&1) res*=n,res%=mod;
        n*=n,n%=mod;
        k>>=1;
    }
    return res;
}

signed main(void) {
    int n,k;
    std::cin >> n >> k;
    int mod = 0;
    std::vector<int> v(n);
    rep(i, n) std::cin >> v[i],mod+=v[i];
    int sum = 0;
    std::reverse(all(v));
    rep(i, n) {
        if(!i&&!v[i]) continue;
        sum+=v[i]*mod_pow(k,i,mod),sum%=mod;
    }
    std::cout << sum << std::endl;
    return 0;
}