#include <cstdio>
using namespace std;
int f[100005];
int sp[500005];
int main(){
  freopen("divk.in", "r", stdin);
  freopen("divk.out", "w", stdout);
  int n, k, a, b;
  long long sol = 0;
  scanf("%d%d%d%d", &n, &k, &a, &b);
  for (int i = 1; i <= n; ++i){
    scanf("%d", &sp[i]);
    sp[i] = (sp[i - 1] + sp[i]) % k;
  }
  for (int i = a; i <= n; ++i){
    f[sp[i - a]]++;
    if (i > b)
      f[sp[i - b - 1]]--;
    sol += f[sp[i]];
  }
  printf("%lld\n", sol);
  return 0;
}