#include <fstream>
#define DIM 500010
using namespace std;
int p[DIM],f[DIM],n,k,a,b,x;
long long sol;
ifstream cin("divk.in");
ofstream cout("divk.out");
int main()
{
    cin>>n>>k>>a>>b;
    for(int i=1; i<=n; i++)
    {
        cin>>x;
        p[i]=(p[i-1]+x)%k;
        if(i>=a)
            f[p[i-a]]++;
        if(i > b)
            f[p[i-b-1]]--;
        sol=sol+f[p[i]];
    }
    cout<<sol;
    return 0;
}