BERLIN- German Chancellor Angela Merkel said on Monday that the migrant crisis presented Germany with a major challenge that would not be resolved anytime soon, urging citizens to show flexibility and patience. 'We stand before a huge national challenge. That will be a central challenge not only for days or months but for a long period of time,' Merkel said during a press conference in Berlin. 'German thoroughness is great, but what we need now is German flexibility,' she added.