#include <stdio.h>

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

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

  register long i;

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

  r[0]=k;
  
  for(i=1;i<=n;++i)
   {
     scanf("%ld\n",&tmp);
     r[i]=(r[i-1]+tmp)%k;
   }

  for(i=a;i<=n;++i)
   {
      if((i>=a)&&(i-a<n))
       ++v[r[i-a]];

      if((i>=b+1)&&(i-b-1<n))
       --v[r[i-b-1]];
       
      sol+=v[r[i]];
   }

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

  return 0;
}
/*
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*/