#include<bits/stdc++.h>
using namespace std;
int sp[500005],v[500005],nr;
int main ()
{
    ifstream cin ("divk.in");
    ofstream cout ("divk.out");
    int n,k,a,b;
    cin>>n>>k>>a>>b;
    int i,j;
    for(i=1;i<=n;i++)
    {
        cin>>j;
        sp[i]=(sp[i-1]+j)%k;
        if(i-b-1>=0)
			--v[sp[i-b-1]];
		if(i-a>=0)
			++v[sp[i-a]];
		nr+=v[sp[i]];
    }
    cout<<nr;
    return 0;
}