#include <fstream>

using namespace std;

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

const int NMAX = 500003,KMAX = 100003;

int v[NMAX],f[KMAX];

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