#include <algorithm>
#include <iostream>
#include <map>
#include <vector>

int main() {
    using namespace std;
    int n, d, t;
    cin >> n >> d >> t;
    map<int, vector<int>> mp;
    while (n--) {
        int x;
        cin >> x;
        mp[(x % d + d) % d].push_back(x / d);
    }

    long long ans = 0;
    for (auto [ignore, vec] : mp) {
        sort(vec.begin(), vec.end());
        int left = vec[0] - t, right = vec[0] + t;
        for (int e : vec) {
            if (right < e - t) {
                ans += right - left + 1;
                left = e - t;
            }
            right = e + t;
        }
        ans += right - left + 1;
    }
    cout << ans << endl;
}