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

using lint = long long;
constexpr lint INF = 1000000000;

void solve() {
    int n;
    lint d, t;
    std::cin >> n >> d >> t;

    std::map<lint, std::vector<int>> xss;
    while (n--) {
        int x;
        std::cin >> x;
        x += INF;
        xss[x % d].push_back(x / d);
    }

    lint ans = 0;
    for (auto& [r, xs] : xss) {
        std::sort(xs.begin(), xs.end());
        lint pr = -INF;

        for (auto x : xs) {
            lint l = std::max(x - t, pr + 1),
                 r = x + t;
            ans += r - l + 1;
            pr = r;
        }
    }

    std::cout << ans << "\n";
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}