On user Input - show alert

On user Input - show alert

Hi,
I cannot save this script on On User Input of a field:

     if (count(Matr_cula_Consular[C_digo_Fisca_CPF == input.C_digo_Fisca_CPF]) > 0) 
{
     input.C_digo_Fisca_CPFerror = “Warning...”;
     show C_digo_Fisca_CPFerror;
}




 
I write something wrong?
 
Mic