#include "bits/stdc++.h"
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> veci;
typedef vector<string> vecs;
//template<class T,class U> using Hash=unordered_map<T,U>;

#define REP(i, a, n) for(ll i = a; i < (ll)n; i++)
#define RREP(i, a, n) for(ll i = n-1; i >= a; i--)
#define rep(i, n) REP(i, 0, n)
#define rrep(i, n) RREP(i, 0, n)
#define MD 1000000007

template<class T> T read(){T a;cin >> a;return a;}
template<class T> void read(T& a){cin >> a;}
template<class T> void rarr(T a, int n){for(int i = 0; i < n; i++) {cin >> a[i];}}
template<class T> void write(T a){cout << a << endl;}
template<class T> void writes(vector<T> a, const char* c = " "){cout << a[0];for(int i = 1; i < (int)a.size(); i++)cout << c << a[i];cout << endl;;}
void write(double a){cout << fixed << setprecision(12) << a << endl;}
void write(long double a){cout << fixed << setprecision(12) << a << endl;}
template<class T> void warr(T a, int n, const char* c = " "){cout << a[0];for(int i = 1; i < n; i++)cout << c << a[i];cout << endl;}
void split(string s, string delim, veci& result){result.clear();string::size_type pos = 0;while(pos != string::npos){string::size_type p = s.find(delim, pos);if(p == string::npos){result.push_back(atoi(s.substr(pos).data()));break;}else {result.push_back(atoi(s.substr(pos, p - pos).data()));}pos = p + delim.size();}}
void split(string s, string delim, vecs& result){result.clear();string::size_type pos = 0;while(pos != string::npos){string::size_type p = s.find(delim, pos);if(p == string::npos){result.push_back(s.substr(pos));break;}else {result.push_back(s.substr(pos, p - pos));}pos = p + delim.size();}}
ll gcd(ll a, ll b){while(true){ll k = a % b;if(k == 0)return b;a = b;b = k;}}
ll comb(ll n, ll m){ll p=1;m=min(m,n-m);for(ll i=1;i<=m;i++){p*=n-i+1;p/=i;}return p;}

int main(void)
{
    ll n,d,t;
    ll x[100];
    pair<ll,int> st[200];
    cin>>n>>d>>t;
    rep(i,n)cin>>x[i];
    sort(x,x+n);
    ll res=n,add=2*n;
    int ct=0;
    rep(i,n){
        ll p=abs(x[i])%d;
        REP(j,i+1,n){
            if(abs(x[j])%d==p){
                ll ti=(x[j]-x[i])/d;
                st[ct].first=(ti+1)/2;
                st[ct].second=(ti%2==0)?1:2;
                ct++;
                break;
            }
        }
        /*
        RREP(j,0,i){
            if(abs(x[j])%d==p){
                ll ti=(x[i]-x[j])/d;
                st[ct].first=(ti+1)/2;
                st[ct].second=(ti%2==1)?1:2;
                ct++;
                break;
            }
        }
        */
    }
    sort(st,st+ct);
    int ii=0;
    ll bef=0;
    while(ii<ct&&st[ii].first<=t){
        res+=(st[ii].first-bef)*add-st[ii].second;
        add-=2;
        bef=st[ii].first;
        ii++;
    }
    res+=(t-bef)*add;
    write(res);
    return 0;
}