#include <fstream>

using namespace std;

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

int n,k,a,b;
int v[500002],s[100002];

int main()
{
    fin >> n >> k >> a >> b;

    long long sol=0;
    for (int i=1;i<=n;i++)
    {
        fin >> v[i];
        v[i]+=v[i-1];
        v[i]%=k;
        if (i-b-1 >= 0) s[v[i-b-1]]--;
        if (i-a>=0) s[v[i-a]]++;
        sol+=s[v[i]];
    }

    fout << sol;
    return 0;
}