View Compilation Error

0_0_23706043_2463.cpp: In function 'int main()':
0_0_23706043_2463.cpp:34:12: error: cannot convert 'std::priority_queue<_Tp, _Sequence, _Compare>::empty<int, std::vector<int>, std::greater<int> >' from type 'bool (std::priority_queue<int, std::vector<int>, std::greater<int> >::)() const' to type 'bool'
   while(!Q.empty)
            ^
0_0_23706043_2463.cpp:34:12: error: in argument to unary !