View Compilation Error

0_0_15938916_26686.cpp: In function 'll work()':
0_0_15938916_26686.cpp:35:2: error: 'deque' was not declared in this scope
  deque<ll> In, o;
  ^
0_0_15938916_26686.cpp:35:10: error: expected primary-expression before '>' token
  deque<ll> In, o;
          ^
0_0_15938916_26686.cpp:35:12: error: 'In' was not declared in this scope
  deque<ll> In, o;
            ^
0_0_15938916_26686.cpp:35:16: error: 'o' was not declared in this scope
  deque<ll> In, o;
                ^