#include <fstream>

using namespace std;

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

int a,b,k,n,v[500010],frecv[100010],ans,i;

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

    for( i = 1 ; i <= n ; i++ )
    {
        fin>>v[ i ];
        v[ i ] = ( v[ i ] + v[ i - 1 ] ) % k;
    }

    for( i = a ; i <= n ; i++ )
    {
        frecv[ v[ i - a ] ]++;
        if( i > b )
            frecv[ v[ i - b - 1 ] ]--;
        ans += frecv[ v[ i ] ];
    }

    fout<<ans;

return 0;
}