#include <fstream>
using namespace std;

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

int n,mod,a,b;
const int nmax{500000};
const int kmax{100000};

int v[nmax + 5];
int f[kmax + 5];
long long sol;
int main()
{
    fin>>n>>mod>>a>>b;
    for(int i=1;i<=n;i++)
    {
        fin>>v[i];
        v[i]+=v[i-1];
        v[i]%=mod;
        if(i>=a)
            f[v[i-a]]++;
        sol += f[v[i]];
        if(i>=b)
            f[v[i-b]]--;
    }
    fout<<sol;
}