#include <fstream>

using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");
int n,k,a,b,x,i,t,c[500002],s[100001];
int main()
{
    fin>>n>>k>>a>>b;
    for(i=1;i<=n;i++)
    {
    	fin>>x;
    	c[i]=c[i-1]+x;
    	c[i]=c[i]%k;
    	if(i>=a)
			s[c[i-a+1]]++;
    	if(i>b)
    		s[c[i-b]]--;
		t=t+s[c[i]];
    }
    fout<<t;
    return 0;
}