#include <iostream>
#include <fstream>

using namespace std;

ifstream in("zombie.in");
ofstream out("zombie.out");

int x[1000100];


int main()
{
    int d,n,k,t,nr,i,ch=0;
    in>>d>>n>>k;
    t=0;
    nr=0;
    for(i=1;i<=n;++i)
    {
        in>>x[i];
        if(t==0)
        {
            t=x[i]+d-1;
            nr=1;
            continue;
        }
        if(t>=x[i])
        {
            ++nr;
            continue;
        }
        if(k<nr)
            ch+=k;
        else
        {
            while(nr!=0 && t<x[i])
            {
               t=x[i-nr+1]+d-1;
               nr--;
               ch++;
            }
            nr++;
        }

    }
    if(k<nr)
        ch+=k;
    else
        ch+=nr;
    out<<ch;
    return 0;
}