ll@n,@k,@x,@y,@a[n];
rep[a](x,n)x=(x-1)/+k;
sortA(n,a);
ll b=max(0,n-y/x);
ll c=b?a[b-1]:0;
//wt(y*c+x*sum[i,b,n](a[i]-c));
wt(y*c+x*sum[i,b,n](a[i])-x*c*(n-b));