#include <fstream>
using namespace std;
#define int long long
ifstream cin("divk.in");
ofstream cout("divk.out");
const int mxN=5e5+50;
int n, k, a, b, ans, v[mxN], f[mxN/5];
int32_t main(){
	cin >> n >> k >> a >> b;
	for(int i=1; i<=n; ++i){
		int x; cin >> x;
		v[i]=(v[i-1]+x)%k;
		if(i-a>=0) ++f[v[i-a]];
		if(i-b>0) --f[v[i-b-1]];
		ans+=f[v[i]];
	}
	cout << ans;
}