Set Exexution Time

Hi!! How can i change the execution time?

After upgrade i’m having this error when i request the visits of my web:
This is the request:
www.domain.com/piwik/?module=API&method=VisitsSummary.getVisits&idSite=1&period=month&date=last20&format=xml&token_auth=xxxxxxxx
This is the ERROR:
PHP Fatal error: Maximum execution time of 60 seconds exceeded in D:\Sitios\Piwik\core\DataTable\Row.php on line 162

Thanks…