#include <iostream>
#include <algorithm>
#include <unordered_map>
#include <vector>

int main() {
    int N, D, T;
    std::cin >> N >> D >> T;
    std::unordered_map<int, std::vector<int>> line;
    std::vector<int> X(N);
    for (int i = 0; i < N; i++) { std::cin >> X.at(i); }

    for (const auto &x: X) {
        line[x % D].push_back(x / D);
    }
    int ans = 0;
    for (auto &[k, v]: line) {
        std::sort(v.begin(), v.end());
        ans += 2 * T + 1;
        for (int i = 0; i < v.size() - 1; i++) {
            ans += v.at(i + 1) + T - std::max({v.at(i + 1) - T - 1, v.at(i) + T});
        }
    }
    std::cout << ans << std::endl;
}