#include <iostream>
#include <fstream>

using namespace std;

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

int v[500001],f[99999];

int main()
{
    int n,a,b,k;
    long long cnt=0;
    fin>>n>>k>>a>>b;
    for(int i=1;i<=n;i++)
    {
        int x;
        fin>>x;
        v[i]=(v[i-1]+x)%k;
        if(i>=a)
            f[v[i-a]]++;
        if(i>b)
            f[v[i-b-1]]--;
        cnt+=f[v[i]];
    }
    fout<<cnt;
    return 0;
}