#include<stdio.h>
int n,k,a,b,v[500010],av[500010],i,j,p[500010];
long long s,sol;
int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    scanf("%d%d%d%d",&n,&k,&a,&b);
    for(i=1;i<=n;i++)
        scanf("%d",&v[i]);
    for(i=1;i<=n;i++)
    {
        s=s+v[i];
        av[i]=s%k;
    }
    p[0]=1;
    for(i=a;i<=n;i++)
    {
        sol+=p[av[i]];
        p[av[i-a+1]]++;
        if(i>=b)
            p[av[i-b]]--;
    }
    printf("%lld",sol);
    return 0;

}