#include <iostream>
#include <map>
#include <vector>
#include <algorithm>
using namespace std;
typedef long long ll;
#define REP(i, n)           for(int(i)=0;(i)<(n);++(i))


map<int,vector<int>> m;

int main(){
    int N,D,T,X;
    cin >> N >> D >> T;
    REP(i,N){
        cin >> X;
        int k = (X+1000000000) % D;
        m[k].push_back((X+1000000000)/D);
    }
    ll res = 0;
    for(auto it = m.begin(); it != m.end(); ++it){
        auto v = it->second;
        sort(v.begin(), v.end());
        ll minv = -(1LL<<62);
        for(auto jt = v.begin(); jt != v.end(); ++jt){
            ll l = *jt - T, r = *jt + T;
            if(minv > l) l = minv+1;
            res += r-l+1;
            minv = r;
        }
    }
    cout << res << endl;
    return 0;
}