#include<iostream>
#include<vector>
using namespace std;

int main(){
    long N, A, B;
    cin >> N >> A >> B;
    vector<long> X(N);
    for (int i=0; i<N; i++){
        cin >> X[i];
    }
    long ans = 0;
    for (int i=0; i<N-1; i++){
        if ((X[i+1]-X[i]) * A < B){
            ans += (X[i+1]-X[i]) * A;
        }
        else ans += B;
    }
    cout << ans << endl;
    return 0;
}
#include <iostream>
#include <string>
#include <vector>
#include <cmath>

#define rep(i,n) for (int i = 0; i < (n); ++i)

using std::cin;
using std::cout;
using std::endl;
using std::string;
using std::vector;

int main() {
  int N, T;
  cin >> N >> T;

  vector<int> t(N);
  rep(i, N) {
    cin >> t[i];
  }

  long long sum = 0;
  rep(i, N-1) {
    sum += std::min(T, t[i+1] - t[i]);
  }
  sum += T;

  cout << sum << endl;

  return 0;
}
