#include <iostream>
using namespace std;
int main(void){
    long long n,a,b,c=0,d,e;
    cin>>n>>a>>b>>d;
    for(int i=1;i<n;i++){
        cin>>e;
        
        if((e-d)*a>b){
            c+=b;
        }else{
            c+=(e-d)*a;
        }
        
        d=e;
    }
    
    cout<<c<<endl;
    
}
