#include <cstdio>
int v[10004],s[500004];
int main()
{
	int n,a,b,k,i,j;
	long long nr=0,x;
	freopen("divk.in","r",stdin);
	freopen("divk.out","w",stdout);
	scanf("%d %d %d %d",&n,&k,&a,&b);
	for (i=1;i<=n;++i)
	{
		scanf("%d",&s[i]);
		s[i]=(s[i]+s[i-1])%k;
		if (i>=a)
		{
			if (i>b) -- v[s[i-b]];
			++v[s[i-a]];
			x=v[s[i]];
			nr+=x;
		}
	}
	printf("%lld",nr);
	return 0;}