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

typedef long long ll;
typedef vector< int > vi;
typedef vector< vi > vvi;
typedef vector< ll > vl;
typedef vector< vl > vvl;
typedef pair< int, int > pii;
typedef vector< pii > vp;
typedef vector< double > vd;
typedef vector< vd > vvd;
typedef vector< string > vs;

template< class T1, class T2 >
int upmin( T1 &x, T2 v ){
  if( x > v ){
    x = v;
    return 1;
  }
  return 0;
}

template< class T1, class T2 >
int upmax( T1 &x, T2 v ){
  if( x < v ){
    x = v;
    return 1;
  }
  return 0;
}

const int INF = 0x3f3f3f3f;

int N, D, T;
vi X;

void init(){
  cin >> N >> D >> T;
  X = vi( N );
  for( int i = 0; i < N; ++i )
    cin >> X[ i ];
}

map< int, vi > mod_group;
ll ans;

void preprocess(){
  sort( X.begin(), X.end() );
  for( int i = 0; i < N; ++i )
    mod_group[ ( X[ i ] % D + D ) % D ].emplace_back( X[ i ] );
  for( auto it = mod_group.begin(); it != mod_group.end(); ++it ){
    ans += 2 * T + 1;
    for( int i = 1; i < ( it->second ).size(); ++i ){
      ans += 2 * T + 1;
      ll lrb = 1LL * T * D + ( it->second )[ i - 1 ];
      ll rlb = 1LL * ( it->second )[ i ] - 1LL * T * D;
      if( rlb <= lrb )
        ans -= ( lrb - rlb ) / D + 1;
    }
  }
}

void solve(){
  cout << ans << endl;
}

signed main(){
  ios::sync_with_stdio( 0 );
  init();
  preprocess();
  solve();
  return 0;
}