#include <stdio.h>

int tmp, n, k, a, b, v[1<<19], r[1<<19];
long long sol;

int main()
{
  freopen("divk.in","r",stdin);
  freopen("divk.out","w",stdout);

  int i;

  scanf("%d %d %d %d\n", &n, &k, &a, &b);
  
  for(i=1;i<=n;++i)
   {
     scanf("%d\n", &tmp);
     r[i]=(r[i-1]+tmp)%k;
   }

  for(i=0;i<=n;++i)
   {
      ++v[r[i]];

      if(i-b>0)
       --v[r[i-b-1]];

      if(i)
       sol+=v[r[i]]-1;
   }

  for(i=0;i<=k;++i)
   v[i]=0;

  b=a-1;
  
  for(i=0;i<=n;++i)
   {

      ++v[r[i]];

      if(i-b>0)
       --v[r[i-b-1]];

      if(i)
       sol-=v[r[i]]-1;
   }


  printf("%lld\n", sol);

  return 0;
}
/*
0 1 2 3 4 5 6
0 2 1 1 0 1 1
  2 9 5 4 1 4

  2 9 4 5
  5 4 1
  4 1
  1 4
*/