#include <fstream>

using namespace std;

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

long long n, k, a, b, sol, v[500010], app[100010];

int main()
{
    long long i, elem;
    fin >> n >> k >> a >> b;
    for(i = 1; i <= n; i++)
    {
        fin >> elem;
        v[i] = (v[i - 1] + elem) % k;
    }
    for(i = 1; i <= n; i++)
    {
        if( i - a >= 0 )
            app[v[i - a]]++;
        if( i - b > 0 )
            app[v[i - b - 1]]--;
        sol += app[v[i]];
    }
    fout << sol;
    return 0;
}