#include <fstream>
using namespace std;
int v[500001],f[99999];
int main()
{
    ifstream cin("divk.in");
    ofstream cout("divk.out");
    long long n,k,a,b,x,c=0;
    cin>>n>>k>>a>>b;
    for(int i=1;i<=n;i++)
    {
        cin>>x;
        v[i]=(v[i-1]+x)%k;
        if(i>=a)
            f[v[i-a]]++;
        if(i>b)
            f[v[i-b-1]]--;
        c+=f[v[i]];
    }
    cout<<c;
    return 0;
}