#include <fstream>


using namespace std;

ifstream fin("divk.in");
ofstream fout("divk.out");
int n,k,a,b,v[500010],d[100010];
int main(){
    fin>>n>>k>>a>>b;
    long long rez = 0;
    for(int i=1;i<=n;i++){
        fin>>v[i];
        v[i]+=v[i-1];
        v[i]%=k;
    }
    for(int i=1;i<=n;i++){
        //suma+=v[i];
        if(i>=a){
            d[v[i-a]]++;
        }
        rez+=d[v[i]];
        if(i>=b)
            d[v[i-b]]--;
    }
    fout<<rez;
    return 0;
}