#include <fstream>
#define nmax 500005
#define kmax 100005
using namespace std;
ifstream f("divk.in");
ofstream g("divk.out");
long long sol;
int n,k,a,b;
int v[nmax];
int p[kmax];

int main()
{
    int i,j,x;
    f>>n>>k>>a>>b;
    for (i=1;i<=n;i++){
        f>>x;
        v[i]=(v[i-1]+x)%k;
    }
    for (i=a;i<=n;i++) {
        p[v[i-a]]++;
        if (i>b)
            p[v[i-b-1]]--;

        sol+=1LL*p[v[i]];
    }

    g<<sol;

    return 0;
}