#include <bits/stdc++.h>
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define FORR(i,a,b) for (int i=(a);i>=(b);i--)
#define pb push_back

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef set<int> si;
const int inf = 1e9;

ll n, d, t, x[100];
map<ll, ll> m;
main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> n >> d >> t;
  FOR(i, 0, n)cin >> x[i];
  sort(x, x+n);
  ll ans = 0;
  FOR(i, 0, n){
    ll y = x[i];
    ll mod = (y%d + d)%d;
    if(m.find(mod) == m.end()){
      ans += t * 2 + 1;
    }else{
      ans += min(t * 2 + 1, (y - m[mod]) / d);
    }
    m[mod] = y;
  }
  cout << ans << endl;
}