#include <fstream>

using namespace std;

ifstream in("divk.in");
ofstream out("divk.out");

long long v[500005],f[500005],n,k,rez,a,b,nr;

int main()
{
    in>>n>>k>>a>>b;
    for ( int i=1; i<=n; i++)
    {
        in>>nr;
        v[i]=(v[i-1]+nr)%k;
        if ( i>=a)
            f[v[i-a]]++;
        if ( i>b)
            f[v[i-b-1]]--;
        rez=rez+f[v[i]];
    }
    out<<rez;
    return 0;
}