#include <bits/stdc++.h>
using namespace std;
int n,k,ans;
int a[5];
int cmp(int a,int b){
	return a>b;
}
int main(){
	cin >> n >> k;
	for(int i = 1;i<=k;i++) cin >> a[i];
	int l = 1,r = n;
	sort(a+1,a+k+1,cmp);
	for(int i = 1;i<=n;i++){
		if(l > r) break;
		else{
			ans += (r-l)*a[i];
			l++;
			r--;
		}
	}
	cout << ans;
	return 0;
}