#include <fstream>

using namespace std;

ifstream fin("divk.in");
ofstream fout("divk.out");

long long n,k,a,b,i,x,af,s[500005],v[500005];

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

    return 0;
}