#include <fstream>

const int NMAX=500005;
const int KMAX=100005;

using namespace std;

int sp[NMAX],f[KMAX];

ifstream cin ("divk.in");
ofstream cout ("divk.out");

int main()
{
    int n,k,a,b;
    cin>>n>>k>>a>>b;
    for(int i=1; i<=n; ++i)
    {
        int x;
        cin>>x;
        sp[i]=(x+sp[i-1])%k;
    }
    long long sol=0;
    for(int i=a; i<=n; ++i)
    {
        f[sp[i-a]]++;
        if(i>b)
            f[sp[i-b-1]]--;
        sol+=f[sp[i]];
    }
    cout<<sol<<'\n';
    return 0;
}