#include <fstream>
#define NMax 500001
using namespace std;
ifstream f("divk.in");
ofstream g("divk.out");
long long n, k, a, b, v[NMax], r[NMax], i, s, el;
int main()
{
    f>>n>>k>>a>>b;
    for (i=1; i<=n; i++) {
        f>>el;
        v[i]=(v[i-1]+el)%k;
    }
    for (i=a; i<=n; i++) {
        r[v[i-a]]++;
        if(i>b)
            r[v[i-b-1]]--;
        s+=r[v[i]];
    }
    g<<s;
    return 0;
}