I'm trying to sort vector of pairs using lambda(don't want to use bool function), and I'm getting error.

    sort(v.begin(),v.end,[](pair<int,int> p1,pair<int,int> p2){return p1.first<p2.first;});

Compiler Build Message:
http://s020.radikal.ru/i701/1412/04/9551a1a9f232.png
And this is Compiler Settings:
http://s019.radikal.ru/i618/1412/24/9a4e6f26ea9d.png
Can you help me?