#include <iostream>
#include <fstream>
#include <algorithm>
#include <cmath>
#include <cstring>
using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");
int v[500001],r[1000000],i,j,a,b,n,k,x,sol,y,start,capat;
int main()
{
fin>>n>>k>>a>>b;x=0;
for(i=1;i<a;i++)
    {fin>>v[i];
    v[i]+=v[i-1];
    v[i]=v[i]%k;
    r[v[i]]++;
    }
start=1;
capat=a;
for(i;i<=n;i++)
{
    fin>>v[i];
    v[i]+=v[i-1];
    v[i]=v[i]%k;
    if(v[i]==0&&i<=b)
        sol++;
    sol+=r[v[i]];
    r[v[i]]++;
    if(capat-start+1>b-a)
    {
        r[v[start]]--;
        start++;
        capat++;
    }
    else
        capat++;

}
fout<<sol;
fin.close();
fout.close();
return 0;
}