#include <fstream>
using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");
int s[500001],v[500001],k,n,a,b,i;
long long nr;

int main(){

    fin>>n>>k>>a>>b;
    for (i=1;i<=n;i++) {
        fin>>s[i];
        s[i]+=s[i-1];
        s[i]%=k;
    }
    for(i=a;i<=n;i++){
        v[s[i-a]]++;
        if(i>b)
            v[s[i-b-1]]--;
        nr+=v[s[i]];
    }
    fout<<nr<<"\n";

    return 0;
}