View Compilation Error

0_0_29963086_21722.cpp: In member function 'bool MCMF::BellmanFord(int, int, int&, int&)':
0_0_29963086_21722.cpp:43:3: error: 'queue' was not declared in this scope
   queue<int> Q;
   ^
0_0_29963086_21722.cpp:43:9: error: expected primary-expression before 'int'
   queue<int> Q;
         ^
0_0_29963086_21722.cpp:44:3: error: 'Q' was not declared in this scope
   Q.push(s);
   ^