#include <fstream>
using namespace std;
ifstream f("divk.in");
ofstream g("divk.out");
const int maxn=500005;
int n, a, b, k, x, s[maxn], nr;

void read()
{
    int i, x;
    f>>n>>k>>a>>b;
    for(i=1; i<=n; ++i)
    {
        f>>x;
        s[i]=s[i-1]+x;
    }
}

void sum(int x, int y, int z)
{
    int i;
    if(x<1) x=1;
    for(i=x; i<=y; ++i) if( (s[z]-s[i]) % k ==0 ) ++nr;
}


int main()
{
    read();
    for(x=a; x<=n; ++x) sum(x-b+1, x-a+1, x);
    g<<nr;
    return 0;
}