#include<iostream>
#include<fstream>
using namespace std;
int a,b,s[500004],f[500004],i,n,k;
long long sol;
int main()
{
    ifstream cin("divk.in");
    ofstream cout("divk.out");
    cin>>n>>k>>a>>b;
    for(i=1;i<=n;i++)
    {
        cin>>s[i];
        s[i]=(s[i]+s[i-1])%k;
        if(i>=a)
            f[s[i-a]]++;
        if(i>b)
            f[s[i-b-1]]--;
        sol+=f[s[i]];
       // cout<<sol<<"\n";
    }
    cout<<sol;
    return 0;
}