#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int,int> P;
int INF = 3e18+7;
int mod = 998244353;
int dx[] = {1, 0,-1, 0, 1, 1,-1,-1};
int dy[] = {0, 1, 0,-1, 1,-1, 1,-1};
int mod_pow(int x,int y) {
    int res = 1;
    while(y > 0) {
        if(y%2) {
            res = res*x%mod;
        }
        x = x*x%mod;
        y/=2;
    }
    return res;
}
signed main() {
    int N,K;
    cin >> N >> K;
    vector<int>A(N);
    int sum = 0;
    for(int i = 0; i < N; i++) {
        cin >> A[i];
        sum += A[i]*mod_pow(N,K)%mod;
        sum %= mod;
        int tmp = A[i];
        tmp *= N;
        tmp %= mod;
        tmp *= (mod_pow(2,K)+mod-1)%mod;
        tmp %= mod;
        tmp *= mod_pow(N,K-1);
        tmp %= mod;
        sum += tmp;
        sum %= mod;
    }
    cout << sum*mod_pow(mod_pow(N,K),mod-2)%mod << endl;
}