#include<fstream>
using namespace std;
int t[1000005],p,l;

int main(void){
    int n,d,k,i=1,j,cost=0; 
    ifstream fin("zombie.in");
    ofstream fout("zombie.out");
    fin>>d>>n>>k; 
    for(i=1;i<=n;++i)fin>>t[i];
    while(i<=n){
         j=i+1;       
         while(t[j]-t[i]<d && j<=n)++j;
            if(k<j-i)cost+=k;
              else cost+=j-i;
         i=j;                                                            
                }                       
    fout<<cost; fout.close(); 
 return 0;   
}