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

#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

#define mygc(c) (c)=getchar_unlocked()
#define mypc(c) putchar_unlocked(c)

#define ll long long
#define ull unsigned ll

template<class T1, class T2> void sort(int N, T1 a[], T2 b[], void *mem){int i;pair<T1,T2> *r=(pair<T1, T2>*)mem;rep(i,N)r[i].first=a[i],r[i].second=b[i];sort(r,r+N);rep(i,N)a[i]=r[i].first,b[i]=r[i].second;}

void reader(int *x){int k,m=0;*x=0;for(;;){mygc(k);if(k=='-'){m=1;break;}if('0'<=k&&k<='9'){*x=k-'0';break;}}for(;;){mygc(k);if(k<'0'||k>'9')break;*x=(*x)*10+k-'0';}if(m)(*x)=-(*x);}
void writer(ll x, char c){int s=0,m=0;char f[20];if(x<0)m=1,x=-x;while(x)f[s++]=x%10,x/=10;if(!s)f[s++]=0;if(m)mypc('-');while(s--)mypc(f[s]+'0');mypc(c);}

int N, D, T;
int X[100];

ll res;
int done[100];
ll st[100], ed[100], sz, bef;

int main(){
  int i, j, k;
  void *mem = malloc(10000000);

  reader(&N); reader(&D); reader(&T);
  rep(i,N) reader(X+i), X[i] += 1000000000;

  rep(k,N) if(!done[k]){

    sz = 0;
    rep(i,N) if((X[i]-X[k])%D==0){
      st[sz] = (ll)X[i] / D;
      ed[sz] = (ll)X[i] / D + 2 * T;
      sz++;
      done[i] = 1;
    }
    sort(sz, st, ed, mem);

    bef = -1;
    rep(i,sz){
      bef = max(bef, st[i]);
      res += ed[i] - bef + 1;
      bef = ed[i] + 1;
    }
  }

  writer(res,'\n');

  return 0;
}