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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    long long N,D,T; cin >> N >> D >> T;
    map<long long,vector<long long>> X;
    for(int i=0; i<N; i++){
        int x; cin >> x;
        int p = x%D+D; p %= D;
        X[p].push_back((x-p)/D);
    }
    long long answer = 0;
    for(auto [ign,A] : X){
        sort(A.begin(),A.end());
        A.erase(unique(A.begin(),A.end()),A.end());
        priority_queue<pair<long long,int>> Q;
        for(auto x : A) Q.push({x+T,1}),Q.push({x-T-1,-1});
        
        long long now = 0,back = 1e18;
        while(Q.size()){
            auto [x,add] = Q.top(); Q.pop();
            if(now > 0) answer += back-x;
            now += add; back = x;
        }
    }
    cout << answer << endl;
}