#include<fstream>
using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");
long long sol;
int n,k,a,b,s[500005],r[100005];
int main()
{
    fin>>n>>k>>a>>b;
    for(int i=1;i<=n;++i)
    {
        fin>>s[i];
        s[i]=(s[i]+s[i-1])%k;
        if(i>=a){r[s[i-a]]++;}
        if(i>b){r[s[i-b-1]]--;}
        sol+=r[s[i]];
    }
    fout<<sol<<"\n";
    return 0;
}