#include <cstdio>
#define filein "divk.in"
#define fileout "divk.out"
using namespace std;

int N,K;
int A,B;
int v[500001];
int r[100000];
long long Answer;

void PrintData();
void PrintR();

int main()
{
    FILE *in;
    in=fopen(filein,"r");
    fscanf(in,"%d%d%d%d",&N,&K,&A,&B);
    register int i;
    for (i=1; i<A; i++)
    {
        fscanf(in,"%d",v+i);
        v[i]+=v[i-1];
        v[i]%=K;
    }
    int st,fn;
    st=0;
    fn=0;
    r[0]=1;
    for (; i<=N; i++)
    {
        fscanf(in,"%d",v+i);
        v[i]+=v[i-1];
        v[i]%=K;
        Answer+=r[v[i]];
        if (fn-st+1>B-A)
        {
            r[v[st++]]--;
            r[v[++fn]]++;
        }
        else
            r[v[++fn]]++;
    }
    fclose(in);
    PrintData();
    return 0;
}

void PrintData()
{
    FILE *out;
    out=fopen(fileout,"w");
    fprintf(out,"%lld",Answer);
    fclose(out);
}