#include <fstream>
#include <cstdio>
 
using namespace std;
 
int v[524288],w[524288];
long long S;
 
int main ()
{
     
    ifstream in ("divk.in");
    freopen ("divk.out","w",stdout);
    int n,k,a,b,x;
    in>>n>>k>>a>>b;
    ++b;
    for(int i=1;i<=n;++i){
        in>>x;
        v[i]=(x+v[i-1])%k;
        }
    for(int i=a;i<=n;++i){
        ++w[v[i-a]];
        if(i>=b)
            --w[v[i-b]];
        S+=w[v[i]];
        }
    printf("%lld",S);
     
    return 0;
}