#include <iostream>
#include <fstream>
#define MAXN 500010
using namespace std;
int ap[MAXN],v[MAXN];
int main()
{
    ifstream in("divk.in");
    ofstream out("divk.out");
    int i,n,x,k,a,b;
    unsigned long long ans=0;
    in>>n>>k>>a>>b;
    for(i=1;i<=n;i++)
    {
        in>>x;
        v[i]=(v[i-1]+x)%k;

    }
    for(i=1;i<=n;i++)
    {
        if(i-a>=0)
            ap[v[i-a]]++;
        if(i-b>0)
            ap[v[i-b-1]]--;
        ans+=ap[v[i]];
    }
    out<<ans;
    return 0;
}