#include <fstream>
#define ll long long
using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");
ll n, k , a, b, sol, v[50010], f[100010], x;
int main()
{
    fin >> n >> k >> a >> b;
    for (ll i = 1; i <= n; ++i)
    {
        fin >> x;
        v[i] = (x + v[i-1]) % k;
    }

    for (ll i = 1; i <= n; ++i)
    {
        if (i - a  >= 0)
            f[v[i-a]]++;
        if (i - b > 0)
            f[v[i-b-1]]--;
        sol+= f[v[i]];
    }
    fout << sol;
    return 0;
}