#include <fstream>
using namespace std;
int main()
{
    ifstream cin("divk.in");
    ofstream cout("divk.out");
    
    int N,K,A,B,x,i,v[100002];
    long long n=0,sum[500001];
    
    cin>>N>>K>>A>>B;

    for(i=1;i<=N;i++)
    {
        cin>>x;

        if(i>B)
        v[sum[i-B-1]]--;
        if(i>=A)
        v[sum[i-A]]++;
        sum[i]=(sum[i-1]+x)%K;

       n+=v[sum[i]];
        
    }

    cout<<n<<"\n";
}