#include<iostream>
#include <fstream.h>
ifstream fin("divk.in");
ofstream fout("divk.out");
int v[10001],s[10001],n,x,y,m;
long long sol=0;
int main ()
{
	fin>>n>>m>>x>>y;
	for(int i=1;i<=n;i++)
	{
		fin>>v[i];
	v[i]=(v[i-1]+v[i])%m;
        if(i>=x)s[v[i-x]]++;
        if(i>y)s[v[i-y-1]]--;
        sol+=s[v[i]];
    }
	fout<<sol;
	return 0;
}