#include <fstream>
#define NMAX 500005
using namespace std;

int sp[NMAX], f[NMAX], x, n, i, k, a, b;
long long sum;

int main()
{
    ifstream fin("divk.in");
    ofstream fout("divk.out");

    fin >> n >> k >> a >> b;

    for(i = 1; i <= n; ++ i)
    {
        fin >> x;
        sp[i] = sp[i - 1] + x;
        sp[i] = sp[i] % k;
    }
    for(i = 1; i <= n; ++ i)
    {
        if(i >= a)
            f[sp[i - a]] ++;

        if(i > b)
            f[sp[i - b - 1]] --;

        sum = sum + f[sp[i]];
    }
    fout << sum << '\n';
    return 0;
}