#include <fstream>

using namespace std;

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

int D[500010],freq[100010],i,j,n,x,a,b,k,ans;

int main()
{
    fin>>n>>k>>a>>b;

    for(i=1 ; i<=n ; ++i)
    {
        fin>>x;
        D[ i ] = ( D[ i - 1 ] + x ) % k;
    }
    freq[ 0 ] = 1;
    for(i=1 ; i<a ; ++i)
        freq[ D[ i ] ]++;

    for(i=a ; i<=n ; ++i)
    {
        if( i >= b )
            freq[ i - b ]--;
        ans += freq[ D[ i ] ];
        freq[ D[ i ] ]++;
    }
    fout<<ans;

return 0;
}