#include <fstream>
#include <iostream>
#include <vector>
#define NMAX 500000

using namespace std;

ifstream f("divk.in");
ofstream g("divk.out");

int n, k, a, b, i, p1, p2, val;
long long sum, sol, x;
vector <int> v[NMAX+10];

void solve(int r)
{   p1 = p2 = 0;
    for(i=1; i<v[r].size(); i++)
        {   val = v[r][i] - b;
            while(v[r][p1] < val) p1++;
            val = v[r][i] - a + 1;
            while(v[r][p2] < val) p2++;
            sol = sol + (long long)p2 - (long long)p1;
        }
}

int main()
{
    f >> n >> k >> a >> b;
    v[0].push_back(0);
    for(i=1; i<=n; i++)
        {   f >> x;
            sum += x;
            v[sum%k].push_back(i);
        }
    for(i=0; i<n; i++) solve(i);
    g << sol << '\n';
    return 0;
}