#include <iostream>
#include <fstream>
#define maxn 500010

using namespace std;

ifstream f("divk.in");
ofstream g("divk.out");

long long n,k,a,b,x,i,v[maxn],r[maxn],s=0;

int main()
{
    f>>n>>k>>a>>b;
    for(i=1;i<=n;i++)
    {
        f>>x;
        v[i] = (v[i-1] + x) % k;
    }
    for(i=1;i<=n;i++)
    {
        if(i>=a)
            r[v[i-a]]++;
        if(i>b)
            r[v[i-b-1]]--;
        s+=r[v[i]];
    }
    g<<s;
}