#include <stdio.h>

int main(){
   int n,k,d;
   int i;
   FILE *fin=fopen("zombie.in","r");
   FILE *fout=fopen("zombie.out","w");
   fscanf(fin,"%d%d%d",&d,&n,&k);
   int t1,tc,x;
   long long chakra=0;
   fscanf(fin,"%d",&t1);
   x=1;
   for(i=1;i<n;i++){
      fscanf(fin,"%d",&tc);
      if(tc-t1>=d){//asta e intervalul
         //la chakra adaug minimuldintre x si k
         if(x<k)chakra+=x;
           else chakra+=k;
         t1=tc;
         x=1;
      }else{
         x++;
      }
   }
         //la chakra adaug minimuldintre x si k
         if(x<k)chakra+=x;
           else chakra+=k;

   fprintf(fout,"%lld\n",chakra);
return 0;
}