#include <fstream>
using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");
int64_t sp[500001];
int fr[100001];
int main()
{
    int n, k, a, b;
    int64_t rez = 0;
    fin >> n >> k >> a >> b;
    for (int i = 1; i <= n; ++i)
    {
        int x;
        fin >> x;
        sp[i] = (sp[i - 1] + x) % k;
        if (i - a >= 0)
            ++fr[sp[i - a]];
        if (i - b - 1 >= 0)
            --fr[sp[i - b - 1]];
        rez += fr[sp[i]];
    }
    fout << rez;
    return 0;
}