#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");
int n, k, a, b;
int x;
long long result;
int main()
{

    fin >> n >> k >> a >> b;
    vector<int> s(n+1);
    vector<int> freq(k);
    for (int i = 1; i <= n; i++)
    {
        fin >> x;
        s[i] = (s[i - 1] + x) % k;
    }

    for (int i = a; i <= n; i++)
    {
        if (i - a >= 0)
            freq[s[i - a]]++;

        result += freq[s[i]];

        if (i - b >= 0)
            freq[s[i - b]]--;
    }

    fout << result;
    return 0;
}