#include <cstdio>
# define DIM 20000000
using namespace std;
int nr,n,k,a,b,x,rest[500005],i,j,sol[100005];
long long soltot;
int poz=0;
char buff[DIM];
void citire(int &numar)
{
    numar=0;
    while(buff[poz]<'0'||buff[poz]>'9')
        if(++poz==DIM)
        fread(buff,1,DIM,stdin),poz=0;
    while('0'<=buff[poz]&&buff[poz]<='9')
    {
        numar=numar*10+buff[poz]-'0';
        if(buff[++poz]==DIM)
               fread(buff,1,DIM,stdin),poz=0;
    }

}
int main(void)
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    citire(n);
    citire(k);
    citire(a);
    citire(b);
    for(i=1;i<=n;i++)
    {
            citire(x);
            rest[i]=(rest[i-1]+x)%k;
            if(i>=a)
            sol[rest[i-a]]++;
            soltot+=sol[rest[i]];
            if(i>=b)
            sol[rest[i-b]]--;

    }
     printf("%lld",soltot);
    return 0;
}