#include<fstream>

using namespace std;

int sp[500005],f[500005];
int main ()
{
    ifstream cin("divk.in");
    ofstream cout("divk.out");
    int n,k,a,b,cnt=0,x;
    cin>>n>>k>>a>>b;
    for(int dr=1;dr<=n;dr++)
    {
        cin>>x;
        sp[dr]=(sp[dr-1]+x)%k;
        if(dr-b-1>=0)
			f[sp[dr-b-1]]--;
		if(dr-a>=0)
			f[sp[dr-a]]++;
		cnt+=f[sp[dr]];
    }
    cout<<cnt;
    return 0;
}