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

using namespace std;
using ll = long long;

#include<map>
int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    ll n,d,t;
    cin>>n>>d>>t;
    ll ans = 0;
    map<ll,vector<ll>> memo;
    for(int i = 0;i<n;i++){
        ll x;
        cin>>x;
        ll now = x % d;
        if(now<0) now += d;
        memo[now].push_back(x);
    }
    for(auto&itr:memo){
        auto now = itr.second;
        sort(now.begin(),now.end());
        ll prev = -1e18;
        for(int i = 0;i<now.size();i++){
            ll le = now[i] - d * t;
            ll ri = now[i] + d * t;
            if(prev<le){
                ans += 2 * t + 1;
                prev = ri;
                continue;
            }
            le = prev;
            ll def = ri - le;
            ans += def / d;
            prev = ri;
        }
    }
    cout<<ans<<endl;
}