#include <iostream>
#include <fstream>
using namespace std;
ifstream f("divk.in");
ofstream g("divk.out");
long long suma;
int n,k,a,b,x[500005],rest[500005];
void solve()
{
    f>>n>>k>>a>>b; int i,y;
    for(i=1;i<=n;i++){f>>y; rest[i]=(rest[i-1]+y)%k;}
    for(i=a;i<=n;i++)
    { x[rest[i-a]]++; suma+=x[rest[i]]; if(i>=b)x[rest[i-b]]--; }
    g<<suma;
}
int main()
{
    solve();
    return 0;
}