#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>

using namespace std;

int main(){

    long long N, D, T, X, ans=0;
    cin >> N >> D >> T;
    map<long long, vector<long long>> mp;
    for (int i=0; i<N; i++){
        cin >> X;
        mp[(X%D+D)%D].push_back(X);
    }

    for (auto &[x, y] : mp) sort(y.begin(), y.end());
    for (auto [x, y] : mp){
        ans += T * 2 + y.size();
        if (y.size() == 1) continue;
        for (int i=0; i<N-1; i++){
            long long Z = (y[i+1] - y[i])/D -1;
            ans += min(Z, T * 2);
        }
    }

    cout << ans << endl;

    return 0;
}