View Compilation Error

0_0_17249210_6928.cpp: In function 'int main()':
0_0_17249210_6928.cpp:31:19: error: 'struct std::pair<const std::basic_string<char>, std::map<std::basic_string<char>, std::basic_string<char> > >' has no member named 'firs'
         cout<<it->firs.t<<":"<<endl;
                   ^