#include <fstream>
using namespace std;
ifstream f("zombie.in");
ofstream g("zombie.out");
int N,K,D,Array[1000002];
long long result;
void Read()
{
    f>>D>>N>>K;
    int i;
    for(i=1;i<=N;i++)
        f>>Array[i];
    result=0;
}
int Binary_Search(int pozition)
{
    int st=pozition+1,dr=N,mid,sol=-1;
    while(st<=dr)
    {
        mid=(st+dr)/2;
        if(Array[mid]-Array[pozition]<=D-1)
        {
            sol=mid;
            st=mid+1;
        }
        else
            dr=mid-1;
    }
    return sol;
}
void Solve()
{
    int i=1;
    while(i<=N)
    {
        int pozition;
        pozition=Binary_Search(i);
        if(pozition==-1)
            result++;
        else
        {
            if(pozition-i+1>=K)
            {
                result+=(long long)K;
                i+=pozition-i+1;
                continue;
            }
            else
            {
                result++;
                i++;
                continue;
            }
        }
        i++;
    }
    g<<result<<"\n";
}
int main()
{
    Read();
    Solve();
    /*for(int i=1;i<=1000000;i++)
        g<<i<<"\n";*/
    return 0;
}