View Compilation Error

0_0_38161337_18491.cpp: In function 'int bfs(int, std::vector<int>&, std::vector<bool>&, int, int)':
0_0_38161337_18491.cpp:10:51: error: expression cannot be used as a function
   int tim = q.front().first, u = q.front().second();
                                                   ^