#include <fstream>
#define KMAX 100003
#define NMAX 500003
using namespace std;

int v[NMAX], i, a, b, n, k, r[KMAX];
long long nr;

ifstream f("divk.in");
ofstream g("divk.out");


int main()
{
    f>>n>>k>>a>>b;
    for (i=1; i<=n; ++i) {
        f>>v[i];
        v[i]=(v[i]+v[i-1])%k;
    }
    for (i=a; i<=n; ++i) {
        ++r[v[i-a]];
        if (i-b-1>=0)
            --r[v[i-b-1]];
        nr+=r[v[i]];
    }
    g<<nr;
    return 0;
}