#include <bits/stdc++.h>
using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");
 
const int NMAX = 5e5 + 5;
int n, k, a, b, v[NMAX], sol[NMAX], ans;
 
int main()
{
    fin >> n >> k >> a >> b;
    for (int i = 1; i <= n; i++)
    {
        fin >> v[i];
        v[i] = (v[i - 1] + v[i]) % k;
        if (i >= a)
           sol[v[i - a]]++;
        if (i > b)
           sol[v[i - b - 1]]--;
        ans += sol[v[i]];
    }
 
    fout << ans ;
    fout.close();
    return 0;
}