#include using namespace std; #define F first #define S second #define R cin>> #define Z class #define ll long long #define ln cout<<'\n' #define in(a) insert(a) #define pb(a) push_back(a) #define pd(a) printf("%.10f\n",a) #define mem(a) memset(a,0,sizeof(a)) #define all(c) (c).begin(),(c).end() #define iter(c) __typeof((c).begin()) #define rrep(i,n) for(ll i=(ll)(n)-1;i>=0;i--) #define REP(i,m,n) for(ll i=(ll)(m);i<(ll)(n);i++) #define rep(i,n) REP(i,0,n) #define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++) ll check(ll n,ll m,ll x,ll y){return x>=0&&x=0&&yvoid pr(const A &a,const B&...b){cout<void PR(A a,ll n){rep(i,n){if(i)cout<<' ';cout< P; ll n,k,x,y,a[111111]; void Main() { cin >> n >> k >> x >> y; rep(i,n) cin >> a[i]; rep(i,n) a[i]=ceil((double)(a[i]-1)/k); sort(a,a+n); ll sum=0; rep(i,n) sum+=a[i]; ll ans=sum*x; rep(i,n) { ll d=a[i]*y; ll c=sum-a[i]*(n-i); d+=c*x; ans=min(ans,d); sum-=a[i]; } pr(ans); } int main(){ios::sync_with_stdio(0);cin.tie(0);Main();return 0;}