#include<stdio.h>
long long n,k,a,b,ap[100007],s[500007],v[500007],sum,i;
int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    scanf("%lld %lld %lld %lld",&n,&k,&a,&b);
    for (i=1;i<=n;i++)
        scanf("%lld",&v[i]);
    for (i=1;i<=n;i++)
        s[i]=(s[i-1]+v[i])%k;
    for(i=1;i<=n;i++)
    {
        if(i-a>=0)
          ++ap[s[i-a]];
        if(i-b>0)
          --ap[s[i-b-1]];
        sum+=ap[s[i]];
    }
    printf("%lld",sum);
}