#include <iostream>
#include <fstream>

using namespace std;

long long s[500010],r[100010];

int main()
{
    ifstream fin("divk.in");
    ofstream fout("divk.out");
    long long i,n,a,b,k,rez=0;
    fin>>n>>k>>a>>b;
    for(i=1;i<=n;i++)
    {
        fin>>s[i];
        s[i]+=s[i-1];
        s[i]=s[i]%k;
    }
    for(i=a;i<=n;i++)
    {
        r[s[i-a+1]]++;
        if(i>b)
            r[s[i-b]]--;
        rez+=r[s[i]];
    }
    fout<<rez;
    return 0;
}