#include <iostream>
using namespace std;
typedef long long ll;

ll n,a,b,p,t,sum=0;

int main(void){
    cin>>n>>a>>b;
    cin>>p;
    for(int i=0;i<n;i++){
        cin>>t;
        sum+=min(b,(t-p)*a);
        p=t;
    }
    cout<<sum<<endl;
}
