#include <stdio.h>

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

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

  scanf("%ld %ld %ld %ld\n", &n, &k, &a, &b);

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

  for(i=1;i<=b;++i)
   ++v[r[i]];

  for(i=b+1;i<=n;++i)
   {
     sol+=v[r[i]];
     --v[r[i-b]];
     ++v[r[i-a+1]];
   }

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

  return 0;
}