#include <fstream>
using namespace std;
ifstream eu("divk.in");
ofstream tu("divk.out");
int X[1000],S[1000],P[1000],K,N,a,b,contor;
void Read()
{
	eu>>N>>K>>a>>b;
	for(int i=0;i<=N;i++)
				{
						eu>>S[i];
						S[i]=(S[i-1]+S[i])%K;
				}
}
void Solve()
{
		for(int i=a;i<=N;i++)
    {
        P[S[i-a]]++;
        if(i>b)
					P[S[i-b-1]]--;
        contor+=P[S[i]];
    }
}
void Print()
{
		tu<<contor<<"\n";
}
int main()
{
		Read();
		Solve();
		Print();
    return 0;
}