#include <fstream>

using namespace std;
int s[500001],ap[500001];
int main()
{ int n,k,a,b,x,i;
long long nr=0;
    ifstream f("divk.in");
    ofstream g("divk.out");
    f>>n>>k>>a>>b;
    for (i=1;i<=n;++i) {
        f>>x;
        s[i]=(s[i-1]+x)%k;
    }
     for (i=a;i<=n;++i) {
        ++ap[s[i-a+1]];
        if (i>b) ap[s[i-b]]--;
        nr+=ap[s[i]];
     }
       g<<nr;
    return 0;
}